diff --git a/poetry.lock b/poetry.lock
index f9ecdc7..4d53e94 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -288,7 +288,7 @@ python-versions = "*"
 
 [[package]]
 name = "mypy"
-version = "0.790"
+version = "0.901"
 description = "Optional static typing for Python"
 category = "dev"
 optional = false
@@ -296,11 +296,13 @@ python-versions = ">=3.5"
 
 [package.dependencies]
 mypy-extensions = ">=0.4.3,<0.5.0"
-typed-ast = ">=1.4.0,<1.5.0"
+toml = "*"
+typed-ast = {version = ">=1.4.0,<1.5.0", markers = "python_version < \"3.8\""}
 typing-extensions = ">=3.7.4"
 
 [package.extras]
 dmypy = ["psutil (>=4.0)"]
+python2 = ["typed-ast (>=1.4.0,<1.5.0)"]
 
 [[package]]
 name = "mypy-extensions"
@@ -704,7 +706,7 @@ testing = ["pytest (>=4.6)", "pytest-checkdocs (>=1.2.3)", "pytest-flake8", "pyt
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.6.9"
-content-hash = "2c327546a054b4f9990bdc98629862f00848f09cb5578c66b808846e854f28dc"
+content-hash = "29b5b12243b13e5b613d4dabcfc486c0478bc4d41df3f34d0b88b7c4a6dbe3aa"
 
 [metadata.files]
 appdirs = [
@@ -835,20 +837,29 @@ mccabe = [
     {file = "mccabe-0.6.1.tar.gz", hash = "sha256:dd8d182285a0fe56bace7f45b5e7d1a6ebcbf524e8f3bd87eb0f125271b8831f"},
 ]
 mypy = [
-    {file = "mypy-0.790-cp35-cp35m-macosx_10_6_x86_64.whl", hash = "sha256:bd03b3cf666bff8d710d633d1c56ab7facbdc204d567715cb3b9f85c6e94f669"},
-    {file = "mypy-0.790-cp35-cp35m-manylinux1_x86_64.whl", hash = "sha256:2170492030f6faa537647d29945786d297e4862765f0b4ac5930ff62e300d802"},
-    {file = "mypy-0.790-cp35-cp35m-win_amd64.whl", hash = "sha256:e86bdace26c5fe9cf8cb735e7cedfe7850ad92b327ac5d797c656717d2ca66de"},
-    {file = "mypy-0.790-cp36-cp36m-macosx_10_9_x86_64.whl", hash = "sha256:e97e9c13d67fbe524be17e4d8025d51a7dca38f90de2e462243ab8ed8a9178d1"},
-    {file = "mypy-0.790-cp36-cp36m-manylinux1_x86_64.whl", hash = "sha256:0d34d6b122597d48a36d6c59e35341f410d4abfa771d96d04ae2c468dd201abc"},
-    {file = "mypy-0.790-cp36-cp36m-win_amd64.whl", hash = "sha256:72060bf64f290fb629bd4a67c707a66fd88ca26e413a91384b18db3876e57ed7"},
-    {file = "mypy-0.790-cp37-cp37m-macosx_10_9_x86_64.whl", hash = "sha256:eea260feb1830a627fb526d22fbb426b750d9f5a47b624e8d5e7e004359b219c"},
-    {file = "mypy-0.790-cp37-cp37m-manylinux1_x86_64.whl", hash = "sha256:c614194e01c85bb2e551c421397e49afb2872c88b5830e3554f0519f9fb1c178"},
-    {file = "mypy-0.790-cp37-cp37m-win_amd64.whl", hash = "sha256:0a0d102247c16ce93c97066443d11e2d36e6cc2a32d8ccc1f705268970479324"},
-    {file = "mypy-0.790-cp38-cp38-macosx_10_9_x86_64.whl", hash = "sha256:cf4e7bf7f1214826cf7333627cb2547c0db7e3078723227820d0a2490f117a01"},
-    {file = "mypy-0.790-cp38-cp38-manylinux1_x86_64.whl", hash = "sha256:af4e9ff1834e565f1baa74ccf7ae2564ae38c8df2a85b057af1dbbc958eb6666"},
-    {file = "mypy-0.790-cp38-cp38-win_amd64.whl", hash = "sha256:da56dedcd7cd502ccd3c5dddc656cb36113dd793ad466e894574125945653cea"},
-    {file = "mypy-0.790-py3-none-any.whl", hash = "sha256:2842d4fbd1b12ab422346376aad03ff5d0805b706102e475e962370f874a5122"},
-    {file = "mypy-0.790.tar.gz", hash = "sha256:2b21ba45ad9ef2e2eb88ce4aeadd0112d0f5026418324176fd494a6824b74975"},
+    {file = "mypy-0.901-cp35-cp35m-macosx_10_9_x86_64.whl", hash = "sha256:91211acf1485a1db0b1261bc5f9ed450cba3c0dfd8da0a6680e94827591e34d7"},
+    {file = "mypy-0.901-cp35-cp35m-manylinux1_x86_64.whl", hash = "sha256:c8bc628961cca4335ac7d1f2ed59b7125d9252fe4c78c3d66d30b50162359c99"},
+    {file = "mypy-0.901-cp35-cp35m-manylinux2010_x86_64.whl", hash = "sha256:4a622faa3be76114cdce009f8ec173401494cf9e8f22713e7ae75fee9d906ab3"},
+    {file = "mypy-0.901-cp35-cp35m-win_amd64.whl", hash = "sha256:8183561bfd950e93eeab8379ae5ec65873c856f5b58498d23aa8691f74c86030"},
+    {file = "mypy-0.901-cp36-cp36m-macosx_10_9_x86_64.whl", hash = "sha256:da914faaa80c25f463913da6db12adba703822a768f452f29f75b40bb4357139"},
+    {file = "mypy-0.901-cp36-cp36m-manylinux1_x86_64.whl", hash = "sha256:307a6c047596d768c3d689734307e47a91596eb9dbb67cfdf7d1fd9117b27f13"},
+    {file = "mypy-0.901-cp36-cp36m-manylinux2010_x86_64.whl", hash = "sha256:a85c6759dcc6a9884131fa06a037bd34352aa3947e7f5d9d5a35652cc3a44bcd"},
+    {file = "mypy-0.901-cp36-cp36m-win_amd64.whl", hash = "sha256:9941b685807b60c58020bb67b3217c9df47820dcd00425f55cdf71f31d3c42d9"},
+    {file = "mypy-0.901-cp37-cp37m-macosx_10_9_x86_64.whl", hash = "sha256:08cf1f31029612e1008a9432337ca4b1fbac989ff7c8200e2c9ec42705cd4c7b"},
+    {file = "mypy-0.901-cp37-cp37m-manylinux1_x86_64.whl", hash = "sha256:bc61153eb4df769538bb4a6e1045f59c2e6119339690ec719feeacbfc3809e89"},
+    {file = "mypy-0.901-cp37-cp37m-manylinux2010_x86_64.whl", hash = "sha256:1cd241966a35036f936d4739bd71a1c64e15f02bf7d12bb2815cccfb2993a9de"},
+    {file = "mypy-0.901-cp37-cp37m-win_amd64.whl", hash = "sha256:97be0e8ed116f7f79472a49cf06dd45dd806771142401f684d4f13ee652a63c0"},
+    {file = "mypy-0.901-cp38-cp38-macosx_10_9_x86_64.whl", hash = "sha256:79beb6741df15395908ecc706b3a593a98804c1d5b5b6bd0c5b03b67c7ac03a0"},
+    {file = "mypy-0.901-cp38-cp38-manylinux1_x86_64.whl", hash = "sha256:bf347c327c48d963bdef5bf365215d3e98b5fddbe5069fc796cec330e8235a20"},
+    {file = "mypy-0.901-cp38-cp38-manylinux2010_x86_64.whl", hash = "sha256:053b92ebae901fc7954677949049f70133f2f63e3e83dc100225c26d6a46fe95"},
+    {file = "mypy-0.901-cp38-cp38-win_amd64.whl", hash = "sha256:f208cc967e566698c4e30a1f65843fc88d8da05a8693bac8b975417e0aee9ced"},
+    {file = "mypy-0.901-cp39-cp39-macosx_10_9_x86_64.whl", hash = "sha256:c86e3f015bfe7958646825d41c0691c6e5a5cd4015e3409b5c29c18a3c712534"},
+    {file = "mypy-0.901-cp39-cp39-macosx_11_0_arm64.whl", hash = "sha256:e8577d30daf1b7b6582020f539f76e78ee1ed64a0323b28c8e0333c45db9369f"},
+    {file = "mypy-0.901-cp39-cp39-manylinux1_x86_64.whl", hash = "sha256:5ddd8f4096d5fc2e7d7bb3924ac22758862163ad2c1cdc902c4b85568160e90a"},
+    {file = "mypy-0.901-cp39-cp39-manylinux2010_x86_64.whl", hash = "sha256:4b54518e399c3f4dc53380d4252c83276b2e60623cfc5274076eb8aae57572ac"},
+    {file = "mypy-0.901-cp39-cp39-win_amd64.whl", hash = "sha256:7845ad3a31407bfbd64c76d032c16ab546d282930f747023bf07c17b054bebc5"},
+    {file = "mypy-0.901-py3-none-any.whl", hash = "sha256:61b10ba18a01d05fc46adbf4f18b0e92178f6b5fd0f45926ffc2a408b5419728"},
+    {file = "mypy-0.901.tar.gz", hash = "sha256:18753a8bb9bcf031ff10009852bd48d781798ecbccf45be5449892e6af4e3f9f"},
 ]
 mypy-extensions = [
     {file = "mypy_extensions-0.4.3-py2.py3-none-any.whl", hash = "sha256:090fedd75945a69ae91ce1303b5824f428daf5a028d2f6ab8a299250a846f15d"},
diff --git a/pyproject.toml b/pyproject.toml
index 0fbd6f5..cca9c75 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -46,7 +46,7 @@ darglint = "^1.7.0"
 isort = "^5.8.0"
 pyupgrade = "^2.11.0"
 black = "^20.8b1"
-mypy = "^0.790"
+mypy = "^0.901"
 bandit = "^1.7.0"
 safety = "^1.10.3"
 pytest = "^6.2.2"