diff --git a/Pipfile.lock b/Pipfile.lock
index 0b9524f..7b69b86 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -228,7 +228,7 @@
                 "sha256:f0b278ce10936db1a37e6954e15a3730bea96a0997c26d7fee88e6c396c2086d",
                 "sha256:f11642dddbb0253cc8853254301b51390ba0081750a8ac03f20ea8103f0c56b6"
             ],
-            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4' and python_version < '4.0'",
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4' and python_version < '4'",
             "version": "==5.5"
         },
         "coveralls": {
@@ -351,18 +351,18 @@
         },
         "ipython": {
             "hashes": [
-                "sha256:714810a5c74f512b69d5f3b944c86e592cee0a5fb9c728e582f074610f6cf038",
-                "sha256:f78c6a3972dde1cc9e4041cbf4de583546314ba52d3c97208e5b6b2221a9cb7d"
+                "sha256:2097be5c814d1b974aea57673176a924c4c8c9583890e7a5f082f547b9975b11",
+                "sha256:f16148f9163e1e526f1008d7c8d966d9c15600ca20d1a754287cf96d00ba6f1d"
             ],
             "index": "pypi",
-            "version": "==7.23.1"
+            "version": "==7.28.0"
         },
         "isort": {
             "hashes": [
                 "sha256:9c2ea1e62d871267b78307fe511c0838ba0da28698c5732d54e2790bf3ba9899",
                 "sha256:e17d6e2b81095c9db0a03a8025a957f334d6ea30b26f9ec70805411e5c7c81f2"
             ],
-            "markers": "python_version < '4.0' and python_full_version >= '3.6.1'",
+            "markers": "python_version < '4' and python_full_version >= '3.6.1'",
             "version": "==5.9.3"
         },
         "jedi": {
@@ -905,7 +905,7 @@
                 "sha256:4987c65554f7a2dbf30c18fd48778ef124af6fab771a377103da0585e2336ece",
                 "sha256:c4fdf4019605b6e5423637e01bc9fe4daef873709a7973e195ceba0a62bbc844"
             ],
-            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4' and python_version < '4.0'",
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4' and python_version < '4'",
             "version": "==1.26.7"
         },
         "virtualenv": {