diff --git a/poetry.lock b/poetry.lock
index c8eb8ad..31a0e80 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -60,7 +60,7 @@ python-versions = ">=3.5"
 dev = ["cloudpickle", "coverage[toml] (>=5.0.2)", "furo", "hypothesis", "mypy (>=0.900,!=0.940)", "pre-commit", "pympler", "pytest (>=4.3.0)", "pytest-mypy-plugins", "sphinx", "sphinx-notfound-page", "zope.interface"]
 docs = ["furo", "sphinx", "sphinx-notfound-page", "zope.interface"]
 tests = ["cloudpickle", "coverage[toml] (>=5.0.2)", "hypothesis", "mypy (>=0.900,!=0.940)", "pympler", "pytest (>=4.3.0)", "pytest-mypy-plugins", "zope.interface"]
-tests_no_zope = ["cloudpickle", "coverage[toml] (>=5.0.2)", "hypothesis", "mypy (>=0.900,!=0.940)", "pympler", "pytest (>=4.3.0)", "pytest-mypy-plugins"]
+tests-no-zope = ["cloudpickle", "coverage[toml] (>=5.0.2)", "hypothesis", "mypy (>=0.900,!=0.940)", "pympler", "pytest (>=4.3.0)", "pytest-mypy-plugins"]
 
 [[package]]
 name = "automat"
@@ -169,7 +169,7 @@ optional = false
 python-versions = ">=3.6.0"
 
 [package.extras]
-unicode_backport = ["unicodedata2"]
+unicode-backport = ["unicodedata2"]
 
 [[package]]
 name = "click"
@@ -407,9 +407,9 @@ python-versions = ">=3.6.1,<4.0"
 
 [package.extras]
 colors = ["colorama (>=0.4.3,<0.5.0)"]
-pipfile_deprecated_finder = ["pipreqs", "requirementslib"]
+pipfile-deprecated-finder = ["pipreqs", "requirementslib"]
 plugins = ["setuptools"]
-requirements_deprecated_finder = ["pip-api", "pipreqs"]
+requirements-deprecated-finder = ["pip-api", "pipreqs"]
 
 [[package]]
 name = "jsonschema"
@@ -686,7 +686,7 @@ toml = "*"
 
 [[package]]
 name = "pytest-cov"
-version = "3.0.0"
+version = "4.0.0"
 description = "Pytest plugin for measuring coverage."
 category = "dev"
 optional = false
@@ -755,7 +755,7 @@ urllib3 = ">=1.21.1,<1.27"
 
 [package.extras]
 socks = ["PySocks (>=1.5.6,!=1.5.7)"]
-use_chardet_on_py3 = ["chardet (>=3.0.2,<6)"]
+use-chardet-on-py3 = ["chardet (>=3.0.2,<6)"]
 
 [[package]]
 name = "service-identity"
@@ -883,21 +883,21 @@ typing-extensions = ">=3.6.5"
 "zope.interface" = ">=4.4.2"
 
 [package.extras]
-all_non_platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
+all-non-platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
 conch = ["appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "cryptography (>=2.6)", "pyasn1"]
-conch_nacl = ["PyNaCl", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "cryptography (>=2.6)", "pyasn1"]
+conch-nacl = ["PyNaCl", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "cryptography (>=2.6)", "pyasn1"]
 contextvars = ["contextvars (>=2.4,<3)"]
 dev = ["coverage (>=6b1,<7)", "pydoctor (>=22.7.0,<22.8.0)", "pyflakes (>=2.2,<3.0)", "python-subunit (>=1.4,<2.0)", "readthedocs-sphinx-ext (>=2.1,<3.0)", "sphinx (>=4.1.2,<6)", "sphinx-rtd-theme (>=0.5,<1.0)", "towncrier (>=19.2,<20.0)", "twistedchecker (>=0.7,<1.0)"]
-dev_release = ["pydoctor (>=22.7.0,<22.8.0)", "readthedocs-sphinx-ext (>=2.1,<3.0)", "sphinx (>=4.1.2,<6)", "sphinx-rtd-theme (>=0.5,<1.0)", "towncrier (>=19.2,<20.0)"]
-gtk_platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pygobject", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
+dev-release = ["pydoctor (>=22.7.0,<22.8.0)", "readthedocs-sphinx-ext (>=2.1,<3.0)", "sphinx (>=4.1.2,<6)", "sphinx-rtd-theme (>=0.5,<1.0)", "towncrier (>=19.2,<20.0)"]
+gtk-platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pygobject", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
 http2 = ["h2 (>=3.0,<5.0)", "priority (>=1.1.0,<2.0)"]
-macos_platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pyobjc-core", "pyobjc-framework-CFNetwork", "pyobjc-framework-Cocoa", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
+macos-platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pyobjc-core", "pyobjc-framework-CFNetwork", "pyobjc-framework-Cocoa", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
 mypy = ["PyHamcrest (>=1.9.0)", "PyNaCl", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "coverage (>=6b1,<7)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "mypy (==0.930)", "mypy-zope (==0.3.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pydoctor (>=22.7.0,<22.8.0)", "pyflakes (>=2.2,<3.0)", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "python-subunit (>=1.4,<2.0)", "pywin32 (!=226)", "readthedocs-sphinx-ext (>=2.1,<3.0)", "service-identity (>=18.1.0)", "sphinx (>=4.1.2,<6)", "sphinx-rtd-theme (>=0.5,<1.0)", "towncrier (>=19.2,<20.0)", "twistedchecker (>=0.7,<1.0)", "types-pyOpenSSL", "types-setuptools"]
-osx_platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pyobjc-core", "pyobjc-framework-CFNetwork", "pyobjc-framework-Cocoa", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
+osx-platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pyobjc-core", "pyobjc-framework-CFNetwork", "pyobjc-framework-Cocoa", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
 serial = ["pyserial (>=3.0)", "pywin32 (!=226)"]
 test = ["PyHamcrest (>=1.9.0)", "cython-test-exception-raiser (>=1.0.2,<2)"]
 tls = ["idna (>=2.4)", "pyopenssl (>=21.0.0)", "service-identity (>=18.1.0)"]
-windows_platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
+windows-platform = ["PyHamcrest (>=1.9.0)", "appdirs (>=1.4.0)", "bcrypt (>=3.0.0)", "contextvars (>=2.4,<3)", "cryptography (>=2.6)", "cython-test-exception-raiser (>=1.0.2,<2)", "h2 (>=3.0,<5.0)", "idna (>=2.4)", "priority (>=1.1.0,<2.0)", "pyasn1", "pyopenssl (>=21.0.0)", "pyserial (>=3.0)", "pywin32 (!=226)", "pywin32 (!=226)", "service-identity (>=18.1.0)"]
 
 [[package]]
 name = "twisted-iocpsupport"
@@ -1615,8 +1615,8 @@ pytest-black = [
     {file = "pytest-black-0.3.12.tar.gz", hash = "sha256:1d339b004f764d6cd0f06e690f6dd748df3d62e6fe1a692d6a5500ac2c5b75a5"},
 ]
 pytest-cov = [
-    {file = "pytest-cov-3.0.0.tar.gz", hash = "sha256:e7f0f5b1617d2210a2cabc266dfe2f4c75a8d32fb89eafb7ad9d06f6d076d470"},
-    {file = "pytest_cov-3.0.0-py3-none-any.whl", hash = "sha256:578d5d15ac4a25e5f961c938b85a05b09fdaae9deef3bb6de9a6e766622ca7a6"},
+    {file = "pytest-cov-4.0.0.tar.gz", hash = "sha256:996b79efde6433cdbd0088872dbc5fb3ed7fe1578b68cdbba634f14bb8dd0470"},
+    {file = "pytest_cov-4.0.0-py3-none-any.whl", hash = "sha256:2feb1b751d66a8bd934e5edfa2e961d11309dc37b73b0eabe73b5945fee20f6b"},
 ]
 pytest-flake8 = [
     {file = "pytest-flake8-1.1.1.tar.gz", hash = "sha256:ba4f243de3cb4c2486ed9e70752c80dd4b636f7ccb27d4eba763c35ed0cd316e"},