diff --git a/poetry.lock b/poetry.lock
index 502f9d9..1ffc411 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -48,14 +48,19 @@ testing = ["pytest", "pytest-flake8", "pytest-cov", "pytest-black (>=0.3.7)", "p
 
 [[package]]
 name = "cfgv"
-version = "2.0.1"
+version = "3.0.0"
 description = "Validate configuration and produce human readable error messages."
 category = "dev"
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
+python-versions = ">=3.6"
 
-[package.dependencies]
-six = "*"
+[[package]]
+name = "cfgv"
+version = "3.3.1"
+description = "Validate configuration and produce human readable error messages."
+category = "dev"
+optional = false
+python-versions = ">=3.6.1"
 
 [[package]]
 name = "colorama"
@@ -76,6 +81,20 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, <4"
 [package.extras]
 toml = ["toml"]
 
+[[package]]
+name = "coverage"
+version = "6.2"
+description = "Code coverage measurement for Python"
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
+[package.dependencies]
+tomli = {version = "*", optional = true, markers = "extra == \"toml\""}
+
+[package.extras]
+toml = ["tomli"]
+
 [[package]]
 name = "distlib"
 version = "0.3.3"
@@ -86,15 +105,15 @@ python-versions = "*"
 
 [[package]]
 name = "filelock"
-version = "3.2.1"
+version = "3.4.0"
 description = "A platform independent file lock."
 category = "dev"
 optional = false
-python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
+python-versions = ">=3.6"
 
 [package.extras]
 docs = ["furo (>=2021.8.17b43)", "sphinx (>=4.1)", "sphinx-autodoc-typehints (>=1.12)"]
-testing = ["coverage (>=4)", "pytest (>=4)", "pytest-cov", "pytest-timeout (>=1.4.2)"]
+testing = ["covdefaults (>=1.2.0)", "coverage (>=4)", "pytest (>=4)", "pytest-cov", "pytest-timeout (>=1.4.2)"]
 
 [[package]]
 name = "identify"
@@ -107,20 +126,33 @@ python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,>=2.7"
 [package.extras]
 license = ["editdistance"]
 
+[[package]]
+name = "identify"
+version = "2.4.0"
+description = "File identification library for Python"
+category = "dev"
+optional = false
+python-versions = ">=3.6.1"
+
+[package.extras]
+license = ["ukkonen"]
+
 [[package]]
 name = "importlib-metadata"
-version = "2.1.2"
+version = "4.8.2"
 description = "Read metadata from Python packages"
 category = "main"
 optional = false
-python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
+python-versions = ">=3.6"
 
 [package.dependencies]
+typing-extensions = {version = ">=3.6.4", markers = "python_version < \"3.8\""}
 zipp = ">=0.5"
 
 [package.extras]
-docs = ["sphinx", "rst.linker"]
-testing = ["packaging", "pep517", "unittest2", "importlib-resources (>=1.3)"]
+docs = ["sphinx", "jaraco.packaging (>=8.2)", "rst.linker (>=1.9)"]
+perf = ["ipython"]
+testing = ["pytest (>=6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytest-cov", "pytest-enabler (>=1.0.1)", "packaging", "pep517", "pyfakefs", "flufl.flake8", "pytest-perf (>=0.9.2)", "pytest-black (>=0.3.7)", "pytest-mypy", "importlib-resources (>=1.3)"]
 
 [[package]]
 name = "importlib-resources"
@@ -136,6 +168,29 @@ zipp = {version = ">=0.4", markers = "python_version < \"3.8\""}
 [package.extras]
 docs = ["sphinx", "rst.linker", "jaraco.packaging"]
 
+[[package]]
+name = "importlib-resources"
+version = "5.4.0"
+description = "Read resources from Python packages"
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
+[package.dependencies]
+zipp = {version = ">=3.1.0", markers = "python_version < \"3.10\""}
+
+[package.extras]
+docs = ["sphinx", "jaraco.packaging (>=8.2)", "rst.linker (>=1.9)"]
+testing = ["pytest (>=6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytest-cov", "pytest-enabler (>=1.0.1)", "pytest-black (>=0.3.7)", "pytest-mypy"]
+
+[[package]]
+name = "iniconfig"
+version = "1.1.1"
+description = "iniconfig: brain-dead simple config-ini parsing"
+category = "dev"
+optional = false
+python-versions = "*"
+
 [[package]]
 name = "jsonschema"
 version = "3.2.0"
@@ -199,6 +254,17 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 [package.dependencies]
 pyparsing = ">=2.0.2"
 
+[[package]]
+name = "packaging"
+version = "21.3"
+description = "Core utilities for Python packages"
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
+[package.dependencies]
+pyparsing = ">=2.0.2,<3.0.5 || >3.0.5"
+
 [[package]]
 name = "pathlib2"
 version = "2.3.6"
@@ -212,11 +278,15 @@ six = "*"
 
 [[package]]
 name = "platformdirs"
-version = "2.0.2"
+version = "2.4.0"
 description = "A small Python module for determining appropriate platform-specific dirs, e.g. a \"user data dir\"."
 category = "dev"
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
+python-versions = ">=3.6"
+
+[package.extras]
+docs = ["Sphinx (>=4)", "furo (>=2021.7.5b38)", "proselint (>=0.10.2)", "sphinx-autodoc-typehints (>=1.12)"]
+test = ["appdirs (==1.4.4)", "pytest (>=6)", "pytest-cov (>=2.7)", "pytest-mock (>=3.6)"]
 
 [[package]]
 name = "pluggy"
@@ -232,6 +302,21 @@ importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 [package.extras]
 dev = ["pre-commit", "tox"]
 
+[[package]]
+name = "pluggy"
+version = "1.0.0"
+description = "plugin and hook calling mechanisms for python"
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
+[package.dependencies]
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
+
+[package.extras]
+dev = ["pre-commit", "tox"]
+testing = ["pytest", "pytest-benchmark"]
+
 [[package]]
 name = "pre-commit"
 version = "1.21.0"
@@ -252,6 +337,24 @@ six = "*"
 toml = "*"
 virtualenv = ">=15.2"
 
+[[package]]
+name = "pre-commit"
+version = "2.16.0"
+description = "A framework for managing and maintaining multi-language pre-commit hooks."
+category = "dev"
+optional = false
+python-versions = ">=3.6.1"
+
+[package.dependencies]
+cfgv = ">=2.0.0"
+identify = ">=1.0.0"
+importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
+importlib-resources = {version = "<5.3", markers = "python_version < \"3.7\""}
+nodeenv = ">=0.11.1"
+pyyaml = ">=5.1"
+toml = "*"
+virtualenv = ">=20.0.8"
+
 [[package]]
 name = "py"
 version = "1.11.0"
@@ -268,6 +371,17 @@ category = "dev"
 optional = false
 python-versions = ">=2.6, !=3.0.*, !=3.1.*, !=3.2.*"
 
+[[package]]
+name = "pyparsing"
+version = "3.0.6"
+description = "Python parsing module"
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
+[package.extras]
+diagrams = ["jinja2", "railroad-diagrams"]
+
 [[package]]
 name = "pyrsistent"
 version = "0.17.3"
@@ -308,6 +422,28 @@ wcwidth = "*"
 checkqa-mypy = ["mypy (==v0.761)"]
 testing = ["argcomplete", "hypothesis (>=3.56)", "mock", "nose", "requests", "xmlschema"]
 
+[[package]]
+name = "pytest"
+version = "6.2.5"
+description = "pytest: simple powerful testing with Python"
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
+[package.dependencies]
+atomicwrites = {version = ">=1.0", markers = "sys_platform == \"win32\""}
+attrs = ">=19.2.0"
+colorama = {version = "*", markers = "sys_platform == \"win32\""}
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
+iniconfig = "*"
+packaging = "*"
+pluggy = ">=0.12,<2.0"
+py = ">=1.8.2"
+toml = "*"
+
+[package.extras]
+testing = ["argcomplete", "hypothesis (>=3.56)", "mock", "nose", "requests", "xmlschema"]
+
 [[package]]
 name = "pytest-cov"
 version = "2.12.1"
@@ -324,6 +460,21 @@ toml = "*"
 [package.extras]
 testing = ["fields", "hunter", "process-tests", "six", "pytest-xdist", "virtualenv"]
 
+[[package]]
+name = "pytest-cov"
+version = "3.0.0"
+description = "Pytest plugin for measuring coverage."
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
+[package.dependencies]
+coverage = {version = ">=5.2.1", extras = ["toml"]}
+pytest = ">=4.6"
+
+[package.extras]
+testing = ["fields", "hunter", "process-tests", "six", "pytest-xdist", "virtualenv"]
+
 [[package]]
 name = "pyyaml"
 version = "5.3.1"
@@ -349,27 +500,20 @@ optional = false
 python-versions = ">=2.6, !=3.0.*, !=3.1.*, !=3.2.*"
 
 [[package]]
-name = "tox"
-version = "3.24.4"
-description = "tox is a generic virtualenv management and test command line tool"
+name = "tomli"
+version = "1.2.2"
+description = "A lil' TOML parser"
 category = "dev"
 optional = false
-python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
-
-[package.dependencies]
-colorama = {version = ">=0.4.1", markers = "platform_system == \"Windows\""}
-filelock = ">=3.0.0"
-importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
-packaging = ">=14"
-pluggy = ">=0.12.0"
-py = ">=1.4.17"
-six = ">=1.14.0"
-toml = ">=0.9.4"
-virtualenv = ">=16.0.0,<20.0.0 || >20.0.0,<20.0.1 || >20.0.1,<20.0.2 || >20.0.2,<20.0.3 || >20.0.3,<20.0.4 || >20.0.4,<20.0.5 || >20.0.5,<20.0.6 || >20.0.6,<20.0.7 || >20.0.7"
+python-versions = ">=3.6"
 
-[package.extras]
-docs = ["pygments-github-lexers (>=0.0.5)", "sphinx (>=2.0.0)", "sphinxcontrib-autoprogram (>=0.1.5)", "towncrier (>=18.5.0)"]
-testing = ["flaky (>=3.4.0)", "freezegun (>=0.3.11)", "psutil (>=5.6.1)", "pytest (>=4.0.0)", "pytest-cov (>=2.5.1)", "pytest-mock (>=1.10.0)", "pytest-randomly (>=1.0.0)", "pytest-xdist (>=1.22.2)", "pathlib2 (>=2.3.3)"]
+[[package]]
+name = "typing-extensions"
+version = "4.0.1"
+description = "Backported and Experimental Type Hints for Python 3.6+"
+category = "main"
+optional = false
+python-versions = ">=3.6"
 
 [[package]]
 name = "virtualenv"
@@ -412,10 +556,22 @@ python-versions = ">=2.7"
 docs = ["sphinx", "jaraco.packaging (>=3.2)", "rst.linker (>=1.9)"]
 testing = ["pathlib2", "unittest2", "jaraco.itertools", "func-timeout"]
 
+[[package]]
+name = "zipp"
+version = "3.6.0"
+description = "Backport of pathlib-compatible object wrapper for zip files"
+category = "main"
+optional = false
+python-versions = ">=3.6"
+
+[package.extras]
+docs = ["sphinx", "jaraco.packaging (>=8.2)", "rst.linker (>=1.9)"]
+testing = ["pytest (>=4.6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytest-cov", "pytest-enabler (>=1.0.1)", "jaraco.itertools", "func-timeout", "pytest-black (>=0.3.7)", "pytest-mypy"]
+
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.5"
-content-hash = "00ef6569f30780a604ea24a0f48bccdb19d974a88f149e5ff9679c8c1c1c8566"
+content-hash = "320217e49ad457c54bfd3b21dc361485fbb98c3beb8b4364872b7b898f4bbee8"
 
 [metadata.files]
 "aspy.yaml" = [
@@ -435,8 +591,10 @@ attrs = [
     {file = "backports.entry_points_selectable-1.1.1.tar.gz", hash = "sha256:914b21a479fde881635f7af5adc7f6e38d6b274be32269070c53b698c60d5386"},
 ]
 cfgv = [
-    {file = "cfgv-2.0.1-py2.py3-none-any.whl", hash = "sha256:fbd93c9ab0a523bf7daec408f3be2ed99a980e20b2d19b50fc184ca6b820d289"},
-    {file = "cfgv-2.0.1.tar.gz", hash = "sha256:edb387943b665bf9c434f717bf630fa78aecd53d5900d2e05da6ad6048553144"},
+    {file = "cfgv-3.0.0-py2.py3-none-any.whl", hash = "sha256:f22b426ed59cd2ab2b54ff96608d846c33dfb8766a67f0b4a6ce130ce244414f"},
+    {file = "cfgv-3.0.0.tar.gz", hash = "sha256:04b093b14ddf9fd4d17c53ebfd55582d27b76ed30050193c14e560770c5360eb"},
+    {file = "cfgv-3.3.1-py2.py3-none-any.whl", hash = "sha256:c6a0883f3917a037485059700b9e75da2464e6c27051014ad85ba6aaa5884426"},
+    {file = "cfgv-3.3.1.tar.gz", hash = "sha256:f5a830efb9ce7a445376bb66ec94c638a9787422f96264c98edc6bdeed8ab736"},
 ]
 colorama = [
     {file = "colorama-0.4.4-py2.py3-none-any.whl", hash = "sha256:9f47eda37229f68eee03b24b9748937c7dc3868f906e8ba69fbcbdd3bc5dc3e2"},
@@ -495,26 +653,81 @@ coverage = [
     {file = "coverage-5.5-pp36-none-any.whl", hash = "sha256:f030f8873312a16414c0d8e1a1ddff2d3235655a2174e3648b4fa66b3f2f1079"},
     {file = "coverage-5.5-pp37-none-any.whl", hash = "sha256:2a3859cb82dcbda1cfd3e6f71c27081d18aa251d20a17d87d26d4cd216fb0af4"},
     {file = "coverage-5.5.tar.gz", hash = "sha256:ebe78fe9a0e874362175b02371bdfbee64d8edc42a044253ddf4ee7d3c15212c"},
+    {file = "coverage-6.2-cp310-cp310-macosx_10_9_x86_64.whl", hash = "sha256:6dbc1536e105adda7a6312c778f15aaabe583b0e9a0b0a324990334fd458c94b"},
+    {file = "coverage-6.2-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:174cf9b4bef0db2e8244f82059a5a72bd47e1d40e71c68ab055425172b16b7d0"},
+    {file = "coverage-6.2-cp310-cp310-manylinux_2_5_i686.manylinux1_i686.manylinux_2_12_i686.manylinux2010_i686.whl", hash = "sha256:92b8c845527eae547a2a6617d336adc56394050c3ed8a6918683646328fbb6da"},
+    {file = "coverage-6.2-cp310-cp310-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:c7912d1526299cb04c88288e148c6c87c0df600eca76efd99d84396cfe00ef1d"},
+    {file = "coverage-6.2-cp310-cp310-musllinux_1_1_aarch64.whl", hash = "sha256:d5d2033d5db1d58ae2d62f095e1aefb6988af65b4b12cb8987af409587cc0739"},
+    {file = "coverage-6.2-cp310-cp310-musllinux_1_1_i686.whl", hash = "sha256:3feac4084291642165c3a0d9eaebedf19ffa505016c4d3db15bfe235718d4971"},
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+    {file = "coverage-6.2-cp38-cp38-manylinux_2_5_i686.manylinux1_i686.manylinux_2_12_i686.manylinux2010_i686.whl", hash = "sha256:a9c8c4283e17690ff1a7427123ffb428ad6a52ed720d550e299e8291e33184dc"},
+    {file = "coverage-6.2-cp38-cp38-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:f614fc9956d76d8a88a88bb41ddc12709caa755666f580af3a688899721efecd"},
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+    {file = "coverage-6.2-cp38-cp38-musllinux_1_1_x86_64.whl", hash = "sha256:63c424e6f5b4ab1cf1e23a43b12f542b0ec2e54f99ec9f11b75382152981df57"},
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+    {file = "coverage-6.2-cp39-cp39-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:215f8afcc02a24c2d9a10d3790b21054b58d71f4b3c6f055d4bb1b15cecce685"},
+    {file = "coverage-6.2-cp39-cp39-manylinux_2_5_i686.manylinux1_i686.manylinux_2_12_i686.manylinux2010_i686.whl", hash = "sha256:a4bdeb0a52d1d04123b41d90a4390b096f3ef38eee35e11f0b22c2d031222c6c"},
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+    {file = "coverage-6.2-cp39-cp39-win_amd64.whl", hash = "sha256:86f2e78b1eff847609b1ca8050c9e1fa3bd44ce755b2ec30e70f2d3ba3844644"},
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+    {file = "coverage-6.2.tar.gz", hash = "sha256:e2cad8093172b7d1595b4ad66f24270808658e11acf43a8f95b41276162eb5b8"},
 ]
 distlib = [
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     {file = "distlib-0.3.3.zip", hash = "sha256:d982d0751ff6eaaab5e2ec8e691d949ee80eddf01a62eaa96ddb11531fe16b05"},
 ]
 filelock = [
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+    {file = "filelock-3.4.0-py3-none-any.whl", hash = "sha256:2e139a228bcf56dd8b2274a65174d005c4a6b68540ee0bdbb92c76f43f29f7e8"},
+    {file = "filelock-3.4.0.tar.gz", hash = "sha256:93d512b32a23baf4cac44ffd72ccf70732aeff7b8050fcaf6d3ec406d954baf4"},
 ]
 identify = [
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     {file = "identify-1.6.2.tar.gz", hash = "sha256:1c2014f6985ed02e62b2e6955578acf069cb2c54859e17853be474bfe7e13bed"},
+    {file = "identify-2.4.0-py2.py3-none-any.whl", hash = "sha256:eba31ca80258de6bb51453084bff4a923187cd2193b9c13710f2516ab30732cc"},
+    {file = "identify-2.4.0.tar.gz", hash = "sha256:a33ae873287e81651c7800ca309dc1f84679b763c9c8b30680e16fbfa82f0107"},
 ]
 importlib-metadata = [
-    {file = "importlib_metadata-2.1.2-py2.py3-none-any.whl", hash = "sha256:cd6a92d78385dd145f5f233b3a6919acf5e8e43922aa9b9dbe78573e3540eb56"},
-    {file = "importlib_metadata-2.1.2.tar.gz", hash = "sha256:09db40742204610ef6826af16e49f0479d11d0d54687d0169ff7fddf8b3f557f"},
+    {file = "importlib_metadata-4.8.2-py3-none-any.whl", hash = "sha256:53ccfd5c134223e497627b9815d5030edf77d2ed573922f7a0b8f8bb81a1c100"},
+    {file = "importlib_metadata-4.8.2.tar.gz", hash = "sha256:75bdec14c397f528724c1bfd9709d660b33a4d2e77387a3358f20b848bb5e5fb"},
 ]
 importlib-resources = [
     {file = "importlib_resources-3.2.1-py2.py3-none-any.whl", hash = "sha256:e2860cf0c4bc999947228d18be154fa3779c5dde0b882bd2d7b3f4d25e698bd6"},
     {file = "importlib_resources-3.2.1.tar.gz", hash = "sha256:a9fe213ab6452708ec1b3f4ec6f2881b8ab3645cb4e5efb7fea2bbf05a91db3b"},
+    {file = "importlib_resources-5.4.0-py3-none-any.whl", hash = "sha256:33a95faed5fc19b4bc16b29a6eeae248a3fe69dd55d4d229d2b480e23eeaad45"},
+    {file = "importlib_resources-5.4.0.tar.gz", hash = "sha256:d756e2f85dd4de2ba89be0b21dba2a3bbec2e871a42a3a16719258a11f87506b"},
+]
+iniconfig = [
+    {file = "iniconfig-1.1.1-py2.py3-none-any.whl", hash = "sha256:011e24c64b7f47f6ebd835bb12a743f2fbe9a26d4cecaa7f53bc4f35ee9da8b3"},
+    {file = "iniconfig-1.1.1.tar.gz", hash = "sha256:bc3af051d7d14b2ee5ef9969666def0cd1a000e121eaea580d4a313df4b37f32"},
 ]
 jsonschema = [
     {file = "jsonschema-3.2.0-py2.py3-none-any.whl", hash = "sha256:4e5b3cf8216f577bee9ce139cbe72eca3ea4f292ec60928ff24758ce626cd163"},
@@ -533,22 +746,28 @@ nodeenv = [
 packaging = [
     {file = "packaging-20.9-py2.py3-none-any.whl", hash = "sha256:67714da7f7bc052e064859c05c595155bd1ee9f69f76557e21f051443c20947a"},
     {file = "packaging-20.9.tar.gz", hash = "sha256:5b327ac1320dc863dca72f4514ecc086f31186744b84a230374cc1fd776feae5"},
+    {file = "packaging-21.3-py3-none-any.whl", hash = "sha256:ef103e05f519cdc783ae24ea4e2e0f508a9c99b2d4969652eed6a2e1ea5bd522"},
+    {file = "packaging-21.3.tar.gz", hash = "sha256:dd47c42927d89ab911e606518907cc2d3a1f38bbd026385970643f9c5b8ecfeb"},
 ]
 pathlib2 = [
     {file = "pathlib2-2.3.6-py2.py3-none-any.whl", hash = "sha256:3a130b266b3a36134dcc79c17b3c7ac9634f083825ca6ea9d8f557ee6195c9c8"},
     {file = "pathlib2-2.3.6.tar.gz", hash = "sha256:7d8bcb5555003cdf4a8d2872c538faa3a0f5d20630cb360e518ca3b981795e5f"},
 ]
 platformdirs = [
-    {file = "platformdirs-2.0.2-py2.py3-none-any.whl", hash = "sha256:0b9547541f599d3d242078ae60b927b3e453f0ad52f58b4d4bc3be86aed3ec41"},
-    {file = "platformdirs-2.0.2.tar.gz", hash = "sha256:3b00d081227d9037bbbca521a5787796b5ef5000faea1e43fd76f1d44b06fcfa"},
+    {file = "platformdirs-2.4.0-py3-none-any.whl", hash = "sha256:8868bbe3c3c80d42f20156f22e7131d2fb321f5bc86a2a345375c6481a67021d"},
+    {file = "platformdirs-2.4.0.tar.gz", hash = "sha256:367a5e80b3d04d2428ffa76d33f124cf11e8fff2acdaa9b43d545f5c7d661ef2"},
 ]
 pluggy = [
     {file = "pluggy-0.13.1-py2.py3-none-any.whl", hash = "sha256:966c145cd83c96502c3c3868f50408687b38434af77734af1e9ca461a4081d2d"},
     {file = "pluggy-0.13.1.tar.gz", hash = "sha256:15b2acde666561e1298d71b523007ed7364de07029219b604cf808bfa1c765b0"},
+    {file = "pluggy-1.0.0-py2.py3-none-any.whl", hash = "sha256:74134bbf457f031a36d68416e1509f34bd5ccc019f0bcc952c7b909d06b37bd3"},
+    {file = "pluggy-1.0.0.tar.gz", hash = "sha256:4224373bacce55f955a878bf9cfa763c1e360858e330072059e10bad68531159"},
 ]
 pre-commit = [
     {file = "pre_commit-1.21.0-py2.py3-none-any.whl", hash = "sha256:f92a359477f3252452ae2e8d3029de77aec59415c16ae4189bcfba40b757e029"},
     {file = "pre_commit-1.21.0.tar.gz", hash = "sha256:8f48d8637bdae6fa70cc97db9c1dd5aa7c5c8bf71968932a380628c25978b850"},
+    {file = "pre_commit-2.16.0-py2.py3-none-any.whl", hash = "sha256:758d1dc9b62c2ed8881585c254976d66eae0889919ab9b859064fc2fe3c7743e"},
+    {file = "pre_commit-2.16.0.tar.gz", hash = "sha256:fe9897cac830aa7164dbd02a4e7b90cae49630451ce88464bca73db486ba9f65"},
 ]
 py = [
     {file = "py-1.11.0-py2.py3-none-any.whl", hash = "sha256:607c53218732647dff4acdfcd50cb62615cedf612e72d1724fb1a0cc6405b378"},
@@ -557,6 +776,8 @@ py = [
 pyparsing = [
     {file = "pyparsing-2.4.7-py2.py3-none-any.whl", hash = "sha256:ef9d7589ef3c200abe66653d3f1ab1033c3c419ae9b9bdb1240a85b024efc88b"},
     {file = "pyparsing-2.4.7.tar.gz", hash = "sha256:c203ec8783bf771a155b207279b9bccb8dea02d8f0c9e5f8ead507bc3246ecc1"},
+    {file = "pyparsing-3.0.6-py3-none-any.whl", hash = "sha256:04ff808a5b90911829c55c4e26f75fa5ca8a2f5f36aa3a51f68e27033341d3e4"},
+    {file = "pyparsing-3.0.6.tar.gz", hash = "sha256:d9bdec0013ef1eb5a84ab39a3b3868911598afa494f5faa038647101504e2b81"},
 ]
 pyrsistent = [
     {file = "pyrsistent-0.17.3.tar.gz", hash = "sha256:2e636185d9eb976a18a8a8e96efce62f2905fea90041958d8cc2a189756ebf3e"},
@@ -585,10 +806,14 @@ pyrsistent = [
 pytest = [
     {file = "pytest-5.4.3-py3-none-any.whl", hash = "sha256:5c0db86b698e8f170ba4582a492248919255fcd4c79b1ee64ace34301fb589a1"},
     {file = "pytest-5.4.3.tar.gz", hash = "sha256:7979331bfcba207414f5e1263b5a0f8f521d0f457318836a7355531ed1a4c7d8"},
+    {file = "pytest-6.2.5-py3-none-any.whl", hash = "sha256:7310f8d27bc79ced999e760ca304d69f6ba6c6649c0b60fb0e04a4a77cacc134"},
+    {file = "pytest-6.2.5.tar.gz", hash = "sha256:131b36680866a76e6781d13f101efb86cf674ebb9762eb70d3082b6f29889e89"},
 ]
 pytest-cov = [
     {file = "pytest-cov-2.12.1.tar.gz", hash = "sha256:261ceeb8c227b726249b376b8526b600f38667ee314f910353fa318caa01f4d7"},
     {file = "pytest_cov-2.12.1-py2.py3-none-any.whl", hash = "sha256:261bb9e47e65bd099c89c3edf92972865210c36813f80ede5277dceb77a4a62a"},
+    {file = "pytest-cov-3.0.0.tar.gz", hash = "sha256:e7f0f5b1617d2210a2cabc266dfe2f4c75a8d32fb89eafb7ad9d06f6d076d470"},
+    {file = "pytest_cov-3.0.0-py3-none-any.whl", hash = "sha256:578d5d15ac4a25e5f961c938b85a05b09fdaae9deef3bb6de9a6e766622ca7a6"},
 ]
 pyyaml = [
     {file = "PyYAML-5.3.1-cp27-cp27m-win32.whl", hash = "sha256:74809a57b329d6cc0fdccee6318f44b9b8649961fa73144a98735b0aaf029f1f"},
@@ -613,9 +838,13 @@ toml = [
     {file = "toml-0.10.2-py2.py3-none-any.whl", hash = "sha256:806143ae5bfb6a3c6e736a764057db0e6a0e05e338b5630894a5f779cabb4f9b"},
     {file = "toml-0.10.2.tar.gz", hash = "sha256:b3bda1d108d5dd99f4a20d24d9c348e91c4db7ab1b749200bded2f839ccbe68f"},
 ]
-tox = [
-    {file = "tox-3.24.4-py2.py3-none-any.whl", hash = "sha256:5e274227a53dc9ef856767c21867377ba395992549f02ce55eb549f9fb9a8d10"},
-    {file = "tox-3.24.4.tar.gz", hash = "sha256:c30b57fa2477f1fb7c36aa1d83292d5c2336cd0018119e1b1c17340e2c2708ca"},
+tomli = [
+    {file = "tomli-1.2.2-py3-none-any.whl", hash = "sha256:f04066f68f5554911363063a30b108d2b5a5b1a010aa8b6132af78489fe3aade"},
+    {file = "tomli-1.2.2.tar.gz", hash = "sha256:c6ce0015eb38820eaf32b5db832dbc26deb3dd427bd5f6556cf0acac2c214fee"},
+]
+typing-extensions = [
+    {file = "typing_extensions-4.0.1-py3-none-any.whl", hash = "sha256:7f001e5ac290a0c0401508864c7ec868be4e701886d5b573a9528ed3973d9d3b"},
+    {file = "typing_extensions-4.0.1.tar.gz", hash = "sha256:4ca091dea149f945ec56afb48dae714f21e8692ef22a395223bcd328961b6a0e"},
 ]
 virtualenv = [
     {file = "virtualenv-20.10.0-py2.py3-none-any.whl", hash = "sha256:4b02e52a624336eece99c96e3ab7111f469c24ba226a53ec474e8e787b365814"},
@@ -628,4 +857,6 @@ wcwidth = [
 zipp = [
     {file = "zipp-1.2.0-py2.py3-none-any.whl", hash = "sha256:e0d9e63797e483a30d27e09fffd308c59a700d365ec34e93cc100844168bf921"},
     {file = "zipp-1.2.0.tar.gz", hash = "sha256:c70410551488251b0fee67b460fb9a536af8d6f9f008ad10ac51f615b6a521b1"},
+    {file = "zipp-3.6.0-py3-none-any.whl", hash = "sha256:9fe5ea21568a0a70e50f273397638d39b03353731e6cbbb3fd8502a33fec40bc"},
+    {file = "zipp-3.6.0.tar.gz", hash = "sha256:71c644c5369f4a6e07636f0aa966270449561fcea2e3d6747b8d23efaa9d7832"},
 ]
diff --git a/pyproject.toml b/pyproject.toml
index 6ae3b9d..ca801f7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,13 +23,21 @@ jsonschema = [
 PyYAML = ">=3.0"
 
 [tool.poetry.dev-dependencies]
-pre-commit = "^1.21"
-pytest = "^5.3"
-pytest-cov = "^2.8"
-tox = "^3.14"
+pre-commit = [
+    {version = "^1.21", python = ">3.5"},
+    {version = "^2.16.0", python = ">3.6"}
+]
+pytest = [
+    {version = "^5.3.0", python = "^3.5"},
+    {version = "^6.2.5", python = ">=3.6"}
+]
+pytest-cov = [
+    {version = "^2.8.0", python = "^3.5"},
+    {version = "^3.0.0", python = ">=3.6"}
+]
 
 [build-system]
-requires = ["poetry>=0.12"]
+requires = ["poetry>=1.1.12"]
 build-backend = "poetry.masonry.api"
 
 [tool.isort]