diff --git a/poetry.lock b/poetry.lock
index f9ecdc7..d9116ce 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -288,19 +288,21 @@ python-versions = "*"
 
 [[package]]
 name = "mypy"
-version = "0.790"
+version = "0.921"
 description = "Optional static typing for Python"
 category = "dev"
 optional = false
-python-versions = ">=3.5"
+python-versions = ">=3.6"
 
 [package.dependencies]
 mypy-extensions = ">=0.4.3,<0.5.0"
-typed-ast = ">=1.4.0,<1.5.0"
+tomli = ">=1.1.0,<3.0.0"
+typed-ast = {version = ">=1.4.0,<2", markers = "python_version < \"3.8\""}
 typing-extensions = ">=3.7.4"
 
 [package.extras]
 dmypy = ["psutil (>=4.0)"]
+python2 = ["typed-ast (>=1.4.0,<2)"]
 
 [[package]]
 name = "mypy-extensions"
@@ -605,6 +607,14 @@ category = "dev"
 optional = false
 python-versions = ">=2.6, !=3.0.*, !=3.1.*, !=3.2.*"
 
+[[package]]
+name = "tomli"
+version = "1.2.3"
+description = "A lil' TOML parser"
+category = "dev"
+optional = false
+python-versions = ">=3.6"
+
 [[package]]
 name = "typed-ast"
 version = "1.4.2"
@@ -704,7 +714,7 @@ 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 = "05a583f57ff796c212adadebcafcb1c2581a293ea326b272ada784a431162936"
 
 [metadata.files]
 appdirs = [
@@ -835,20 +845,26 @@ 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-0.921-cp310-cp310-macosx_10_9_x86_64.whl", hash = "sha256:d9d6a9c35ac1e5d89d9f71f60d4932dfba00b8d2cb0ba758293f0214c851d2c0"},
+    {file = "mypy-0.921-cp310-cp310-macosx_11_0_arm64.whl", hash = "sha256:01ff922b9fa13f451ce51f7b707c97e35b5dd6ad0104a83d598306255cc7f990"},
+    {file = "mypy-0.921-cp310-cp310-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:279d87385acc33d4117612002026d09ef039845dee2cab41d2cca38ca63a72b3"},
+    {file = "mypy-0.921-cp310-cp310-win_amd64.whl", hash = "sha256:f4688e06b2bbb9708eda50bf119abf072833687ca25c11caf84371fb44722b8a"},
+    {file = "mypy-0.921-cp36-cp36m-macosx_10_9_x86_64.whl", hash = "sha256:54bfe651425cc0935e056327c8f0da749015d64e1586601a9350363f4a3a7794"},
+    {file = "mypy-0.921-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:aadc06bffbe00c285771056e5b0364bc3e0a814e3a08d2cc64f4b12ea40bc283"},
+    {file = "mypy-0.921-cp36-cp36m-win_amd64.whl", hash = "sha256:49e528bf13d54a4cbb163fc7532ae220edf0b1bb79070481c77a0c83cc4e36ce"},
+    {file = "mypy-0.921-cp37-cp37m-macosx_10_9_x86_64.whl", hash = "sha256:1952b1c8e84eb03375b5e339295a96b92dd5b865d2a9768431c9c5aa58f8d32b"},
+    {file = "mypy-0.921-cp37-cp37m-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:2d816a6e2114c473181e0df3013decb9a02acbc57d45454357a05258acd528a3"},
+    {file = "mypy-0.921-cp37-cp37m-win_amd64.whl", hash = "sha256:777fc39141b8a4154c61cc6dc0315b25832b8b6efe5a2bef1dba66d5544341d4"},
+    {file = "mypy-0.921-cp38-cp38-macosx_10_9_x86_64.whl", hash = "sha256:8fcad97e6be583c7de2d18304581dc7f8c42ce4950df5d56005bd3efd53e9ef9"},
+    {file = "mypy-0.921-cp38-cp38-macosx_11_0_arm64.whl", hash = "sha256:71c193bc6dc1b2f183b59f6473a13e627885751d9e534fd26bf15bc8eeed8772"},
+    {file = "mypy-0.921-cp38-cp38-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:b64e64fb6092c86239a7b10437c8e0b9b013e704ecdf8bdfaa8d80dbd7ba2a73"},
+    {file = "mypy-0.921-cp38-cp38-win_amd64.whl", hash = "sha256:02aca528afcb965ea7bf2bc5fbe5736225b5786e135d64cce5075e3bc8b785a4"},
+    {file = "mypy-0.921-cp39-cp39-macosx_10_9_x86_64.whl", hash = "sha256:59f6280e3cbb961b7a9957b6e1739c60fd027743c5ec4d3636f1ae24d5249528"},
+    {file = "mypy-0.921-cp39-cp39-macosx_11_0_arm64.whl", hash = "sha256:549557f7dc7ddd45ca08df0944b7f6519a0e23e6336ef3ff260a4e100fe1ccb3"},
+    {file = "mypy-0.921-cp39-cp39-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:b6f6bc11222b61fa805371f18d70f1546f5ca26db5eda8ad9a75364460bd17a0"},
+    {file = "mypy-0.921-cp39-cp39-win_amd64.whl", hash = "sha256:8c2cff600d34ea8f3426a470e0ea75bd35c75269f6df69a9320c99b4e92edca4"},
+    {file = "mypy-0.921-py3-none-any.whl", hash = "sha256:6e57f340ea04a6f7c67c7757e573bc61c2cc096f87ebd829d7c3264dedc0bc54"},
+    {file = "mypy-0.921.tar.gz", hash = "sha256:eca089d7053dff45d6dcd5bf67f1cabc311591e85d378917d97363e7c13da088"},
 ]
 mypy-extensions = [
     {file = "mypy_extensions-0.4.3-py2.py3-none-any.whl", hash = "sha256:090fedd75945a69ae91ce1303b5824f428daf5a028d2f6ab8a299250a846f15d"},
@@ -1091,6 +1107,10 @@ toml = [
     {file = "toml-0.10.2-py2.py3-none-any.whl", hash = "sha256:806143ae5bfb6a3c6e736a764057db0e6a0e05e338b5630894a5f779cabb4f9b"},
     {file = "toml-0.10.2.tar.gz", hash = "sha256:b3bda1d108d5dd99f4a20d24d9c348e91c4db7ab1b749200bded2f839ccbe68f"},
 ]
+tomli = [
+    {file = "tomli-1.2.3-py3-none-any.whl", hash = "sha256:e3069e4be3ead9668e21cb9b074cd948f7b3113fd9c8bba083f48247aab8b11c"},
+    {file = "tomli-1.2.3.tar.gz", hash = "sha256:05b6166bff487dc068d322585c7ea4ef78deed501cc124060e0f238e89a9231f"},
+]
 typed-ast = [
     {file = "typed_ast-1.4.2-cp35-cp35m-manylinux1_i686.whl", hash = "sha256:7703620125e4fb79b64aa52427ec192822e9f45d37d4b6625ab37ef403e1df70"},
     {file = "typed_ast-1.4.2-cp35-cp35m-manylinux1_x86_64.whl", hash = "sha256:c9aadc4924d4b5799112837b226160428524a9a45f830e0d0f184b19e4090487"},
diff --git a/pyproject.toml b/pyproject.toml
index 0fbd6f5..5c657e7 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 = "^0.921"
 bandit = "^1.7.0"
 safety = "^1.10.3"
 pytest = "^6.2.2"