diff --git a/poetry.lock b/poetry.lock
index 29b031c..9e7b613 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -19,11 +19,11 @@ cached-property = "*"
 
 [[package]]
 name = "astroid"
-version = "2.9.0"
+version = "2.9.2"
 description = "An abstract syntax tree for Python with inference support."
 category = "dev"
 optional = false
-python-versions = "~=3.6"
+python-versions = ">=3.6.2"
 
 [package.dependencies]
 lazy-object-proxy = ">=1.4.0"
@@ -40,17 +40,17 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
 [[package]]
 name = "attrs"
-version = "21.2.0"
+version = "21.4.0"
 description = "Classes Without Boilerplate"
 category = "dev"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
 
 [package.extras]
-dev = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins", "zope.interface", "furo", "sphinx", "sphinx-notfound-page", "pre-commit"]
+dev = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins", "zope.interface", "furo", "sphinx", "sphinx-notfound-page", "pre-commit", "cloudpickle"]
 docs = ["furo", "sphinx", "zope.interface", "sphinx-notfound-page"]
-tests = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins", "zope.interface"]
-tests_no_zope = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins"]
+tests = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins", "zope.interface", "cloudpickle"]
+tests_no_zope = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>=4.3.0)", "six", "mypy", "pytest-mypy-plugins", "cloudpickle"]
 
 [[package]]
 name = "babel"
@@ -63,18 +63,6 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 [package.dependencies]
 pytz = ">=2015.7"
 
-[[package]]
-name = "backports.entry-points-selectable"
-version = "1.1.1"
-description = "Compatibility shim providing selectable entry points for older implementations"
-category = "dev"
-optional = false
-python-versions = ">=2.7"
-
-[package.extras]
-docs = ["sphinx", "jaraco.packaging (>=8.2)", "rst.linker (>=1.9)"]
-testing = ["pytest", "pytest-flake8", "pytest-cov", "pytest-black (>=0.3.7)", "pytest-mypy", "pytest-checkdocs (>=2.4)", "pytest-enabler (>=1.0.1)"]
-
 [[package]]
 name = "black"
 version = "21.12b0"
@@ -184,11 +172,11 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
 
 [[package]]
 name = "filelock"
-version = "3.4.0"
+version = "3.4.2"
 description = "A platform independent file lock."
 category = "dev"
 optional = false
-python-versions = ">=3.6"
+python-versions = ">=3.7"
 
 [package.extras]
 docs = ["furo (>=2021.8.17b43)", "sphinx (>=4.1)", "sphinx-autodoc-typehints (>=1.12)"]
@@ -209,7 +197,7 @@ pyflakes = ">=2.3.0,<2.4.0"
 
 [[package]]
 name = "identify"
-version = "2.4.0"
+version = "2.4.1"
 description = "File identification library for Python"
 category = "dev"
 optional = false
@@ -351,11 +339,11 @@ python-versions = ">=3.6"
 
 [[package]]
 name = "platformdirs"
-version = "2.4.0"
+version = "2.4.1"
 description = "A small Python module for determining appropriate platform-specific dirs, e.g. a \"user data dir\"."
 category = "dev"
 optional = false
-python-versions = ">=3.6"
+python-versions = ">=3.7"
 
 [package.extras]
 docs = ["Sphinx (>=4)", "furo (>=2021.7.5b38)", "proselint (>=0.10.2)", "sphinx-autodoc-typehints (>=1.12)"]
@@ -426,7 +414,7 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
 [[package]]
 name = "pygments"
-version = "2.10.0"
+version = "2.11.1"
 description = "Pygments is a syntax highlighting package written in Python."
 category = "main"
 optional = true
@@ -507,7 +495,7 @@ python-versions = "*"
 
 [[package]]
 name = "pyupgrade"
-version = "2.29.1"
+version = "2.31.0"
 description = "A tool to automatically upgrade syntax for newer versions."
 category = "dev"
 optional = false
@@ -526,7 +514,7 @@ python-versions = ">=3.6"
 
 [[package]]
 name = "requests"
-version = "2.26.0"
+version = "2.27.0"
 description = "Python HTTP for Humans."
 category = "main"
 optional = true
@@ -724,7 +712,7 @@ python-versions = ">=3.6"
 
 [[package]]
 name = "tox"
-version = "3.24.4"
+version = "3.24.5"
 description = "tox is a generic virtualenv management and test command line tool"
 category = "dev"
 optional = false
@@ -742,7 +730,7 @@ virtualenv = ">=16.0.0,<20.0.0 || >20.0.0,<20.0.1 || >20.0.1,<20.0.2 || >20.0.2,
 
 [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)"]
+testing = ["flaky (>=3.4.0)", "freezegun (>=0.3.11)", "pytest (>=4.0.0)", "pytest-cov (>=2.5.1)", "pytest-mock (>=1.10.0)", "pytest-randomly (>=1.0.0)", "psutil (>=5.6.1)", "pathlib2 (>=2.3.3)"]
 
 [[package]]
 name = "typing-extensions"
@@ -767,14 +755,13 @@ socks = ["PySocks (>=1.5.6,!=1.5.7,<2.0)"]
 
 [[package]]
 name = "virtualenv"
-version = "20.10.0"
+version = "20.13.0"
 description = "Virtual Python Environment builder"
 category = "dev"
 optional = false
 python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
 
 [package.dependencies]
-"backports.entry-points-selectable" = ">=1.0.4"
 distlib = ">=0.3.1,<1"
 filelock = ">=3.2,<4"
 platformdirs = ">=2,<3"
@@ -810,25 +797,21 @@ alabaster = [
     {file = "aspy.refactor_imports-2.2.0.tar.gz", hash = "sha256:78ca24122963fd258ebfc4a8dc708d23a18040ee39dca8767675821e84e9ea0a"},
 ]
 astroid = [
-    {file = "astroid-2.9.0-py3-none-any.whl", hash = "sha256:776ca0b748b4ad69c00bfe0fff38fa2d21c338e12c84aa9715ee0d473c422778"},
-    {file = "astroid-2.9.0.tar.gz", hash = "sha256:5939cf55de24b92bda00345d4d0659d01b3c7dafb5055165c330bc7c568ba273"},
+    {file = "astroid-2.9.2-py3-none-any.whl", hash = "sha256:aa296702f1a5c3102c860de49473aaa90a7f6d221555d5cf2678940a9be32a4e"},
+    {file = "astroid-2.9.2.tar.gz", hash = "sha256:72ace9c3333e274e9248168fc4f3e300da8545af1c303bd69197027f49e2bfff"},
 ]
 atomicwrites = [
     {file = "atomicwrites-1.4.0-py2.py3-none-any.whl", hash = "sha256:6d1784dea7c0c8d4a5172b6c620f40b6e4cbfdf96d783691f2e1302a7b88e197"},
     {file = "atomicwrites-1.4.0.tar.gz", hash = "sha256:ae70396ad1a434f9c7046fd2dd196fc04b12f9e91ffb859164193be8b6168a7a"},
 ]
 attrs = [
-    {file = "attrs-21.2.0-py2.py3-none-any.whl", hash = "sha256:149e90d6d8ac20db7a955ad60cf0e6881a3f20d37096140088356da6c716b0b1"},
-    {file = "attrs-21.2.0.tar.gz", hash = "sha256:ef6aaac3ca6cd92904cdd0d83f629a15f18053ec84e6432106f7a4d04ae4f5fb"},
+    {file = "attrs-21.4.0-py2.py3-none-any.whl", hash = "sha256:2d27e3784d7a565d36ab851fe94887c5eccd6a463168875832a1be79c82828b4"},
+    {file = "attrs-21.4.0.tar.gz", hash = "sha256:626ba8234211db98e869df76230a137c4c40a12d72445c45d5f5b716f076e2fd"},
 ]
 babel = [
     {file = "Babel-2.9.1-py2.py3-none-any.whl", hash = "sha256:ab49e12b91d937cd11f0b67cb259a57ab4ad2b59ac7a3b41d6c06c0ac5b0def9"},
     {file = "Babel-2.9.1.tar.gz", hash = "sha256:bc0c176f9f6a994582230df350aa6e05ba2ebe4b3ac317eab29d9be5d2768da0"},
 ]
-"backports.entry-points-selectable" = [
-    {file = "backports.entry_points_selectable-1.1.1-py2.py3-none-any.whl", hash = "sha256:7fceed9532a7aa2bd888654a7314f864a3c16a4e710b34a58cfc0f08114c663b"},
-    {file = "backports.entry_points_selectable-1.1.1.tar.gz", hash = "sha256:914b21a479fde881635f7af5adc7f6e38d6b274be32269070c53b698c60d5386"},
-]
 black = [
     {file = "black-21.12b0-py3-none-any.whl", hash = "sha256:a615e69ae185e08fdd73e4715e260e2479c861b5740057fde6e8b4e3b7dd589f"},
     {file = "black-21.12b0.tar.gz", hash = "sha256:77b80f693a569e2e527958459634f18df9b0ba2625ba4e0c2d5da5be42e6f2b3"},
@@ -915,16 +898,16 @@ docutils = [
     {file = "docutils-0.16.tar.gz", hash = "sha256:c2de3a60e9e7d07be26b7f2b00ca0309c207e06c100f9cc2a94931fc75a478fc"},
 ]
 filelock = [
-    {file = "filelock-3.4.0-py3-none-any.whl", hash = "sha256:2e139a228bcf56dd8b2274a65174d005c4a6b68540ee0bdbb92c76f43f29f7e8"},
-    {file = "filelock-3.4.0.tar.gz", hash = "sha256:93d512b32a23baf4cac44ffd72ccf70732aeff7b8050fcaf6d3ec406d954baf4"},
+    {file = "filelock-3.4.2-py3-none-any.whl", hash = "sha256:cf0fc6a2f8d26bd900f19bf33915ca70ba4dd8c56903eeb14e1e7a2fd7590146"},
+    {file = "filelock-3.4.2.tar.gz", hash = "sha256:38b4f4c989f9d06d44524df1b24bd19e167d851f19b50bf3e3559952dddc5b80"},
 ]
 flake8 = [
     {file = "flake8-3.9.2-py2.py3-none-any.whl", hash = "sha256:bf8fd333346d844f616e8d47905ef3a3384edae6b4e9beb0c5101e25e3110907"},
     {file = "flake8-3.9.2.tar.gz", hash = "sha256:07528381786f2a6237b061f6e96610a4167b226cb926e2aa2b6b1d78057c576b"},
 ]
 identify = [
-    {file = "identify-2.4.0-py2.py3-none-any.whl", hash = "sha256:eba31ca80258de6bb51453084bff4a923187cd2193b9c13710f2516ab30732cc"},
-    {file = "identify-2.4.0.tar.gz", hash = "sha256:a33ae873287e81651c7800ca309dc1f84679b763c9c8b30680e16fbfa82f0107"},
+    {file = "identify-2.4.1-py2.py3-none-any.whl", hash = "sha256:0192893ff68b03d37fed553e261d4a22f94ea974093aefb33b29df2ff35fed3c"},
+    {file = "identify-2.4.1.tar.gz", hash = "sha256:64d4885e539f505dd8ffb5e93c142a1db45480452b1594cacd3e91dca9a984e9"},
 ]
 idna = [
     {file = "idna-3.3-py3-none-any.whl", hash = "sha256:84d9dd047ffa80596e0f246e2eab0b391788b0503584e8945f2368256d2735ff"},
@@ -1124,8 +1107,8 @@ pillow = [
     {file = "Pillow-8.4.0.tar.gz", hash = "sha256:b8e2f83c56e141920c39464b852de3719dfbfb6e3c99a2d8da0edf4fb33176ed"},
 ]
 platformdirs = [
-    {file = "platformdirs-2.4.0-py3-none-any.whl", hash = "sha256:8868bbe3c3c80d42f20156f22e7131d2fb321f5bc86a2a345375c6481a67021d"},
-    {file = "platformdirs-2.4.0.tar.gz", hash = "sha256:367a5e80b3d04d2428ffa76d33f124cf11e8fff2acdaa9b43d545f5c7d661ef2"},
+    {file = "platformdirs-2.4.1-py3-none-any.whl", hash = "sha256:1d7385c7db91728b83efd0ca99a5afb296cab9d0ed8313a45ed8ba17967ecfca"},
+    {file = "platformdirs-2.4.1.tar.gz", hash = "sha256:440633ddfebcc36264232365d7840a970e75e1018d15b4327d11f91909045fda"},
 ]
 pluggy = [
     {file = "pluggy-1.0.0-py2.py3-none-any.whl", hash = "sha256:74134bbf457f031a36d68416e1509f34bd5ccc019f0bcc952c7b909d06b37bd3"},
@@ -1152,8 +1135,8 @@ pyflakes = [
     {file = "pyflakes-2.3.1.tar.gz", hash = "sha256:f5bc8ecabc05bb9d291eb5203d6810b49040f6ff446a756326104746cc00c1db"},
 ]
 pygments = [
-    {file = "Pygments-2.10.0-py3-none-any.whl", hash = "sha256:b8e67fe6af78f492b3c4b3e2970c0624cbf08beb1e493b2c99b9fa1b67a20380"},
-    {file = "Pygments-2.10.0.tar.gz", hash = "sha256:f398865f7eb6874156579fdf36bc840a03cab64d1cde9e93d68f46a425ec52c6"},
+    {file = "Pygments-2.11.1-py3-none-any.whl", hash = "sha256:9135c1af61eec0f650cd1ea1ed8ce298e54d56bcd8cc2ef46edd7702c171337c"},
+    {file = "Pygments-2.11.1.tar.gz", hash = "sha256:59b895e326f0fb0d733fd28c6839bd18ad0687ba20efc26d4277fd1d30b971f4"},
 ]
 pylint = [
     {file = "pylint-2.12.2-py3-none-any.whl", hash = "sha256:daabda3f7ed9d1c60f52d563b1b854632fd90035bcf01443e234d3dc794e3b74"},
@@ -1176,8 +1159,8 @@ pytz = [
     {file = "pytz-2021.3.tar.gz", hash = "sha256:acad2d8b20a1af07d4e4c9d2e9285c5ed9104354062f275f3fcd88dcef4f1326"},
 ]
 pyupgrade = [
-    {file = "pyupgrade-2.29.1-py2.py3-none-any.whl", hash = "sha256:1d3f03d14652caacd6f3d464696e103ef33578531a5c1b995be3821b14b811b7"},
-    {file = "pyupgrade-2.29.1.tar.gz", hash = "sha256:737e02bed0de70247df5d2a0c3edba6b4529adf44f5ef588ecda4a69f14bf694"},
+    {file = "pyupgrade-2.31.0-py2.py3-none-any.whl", hash = "sha256:0a62c5055f854d7f36e155b7ee8920561bf0399c53edd975cf02436eef8937fc"},
+    {file = "pyupgrade-2.31.0.tar.gz", hash = "sha256:80e2308cae2b11c3fdd091137495d99abf7e0cd98b501aa5758974991497c24c"},
 ]
 pyyaml = [
     {file = "PyYAML-6.0-cp310-cp310-macosx_10_9_x86_64.whl", hash = "sha256:d4db7c7aef085872ef65a8fd7d6d09a14ae91f691dec3e87ee5ee0539d516f53"},
@@ -1215,8 +1198,8 @@ pyyaml = [
     {file = "PyYAML-6.0.tar.gz", hash = "sha256:68fb519c14306fec9720a2a5b45bc9f0c8d1b9c72adf45c37baedfcd949c35a2"},
 ]
 requests = [
-    {file = "requests-2.26.0-py2.py3-none-any.whl", hash = "sha256:6c1246513ecd5ecd4528a0906f910e8f0f9c6b8ec72030dc9fd154dc1a6efd24"},
-    {file = "requests-2.26.0.tar.gz", hash = "sha256:b8aa58f8cf793ffd8782d3d8cb19e66ef36f7aba4353eec859e74678b01b07a7"},
+    {file = "requests-2.27.0-py2.py3-none-any.whl", hash = "sha256:f71a09d7feba4a6b64ffd8e9d9bc60f9bf7d7e19fd0e04362acb1cfc2e3d98df"},
+    {file = "requests-2.27.0.tar.gz", hash = "sha256:8e5643905bf20a308e25e4c1dd379117c09000bf8a82ebccc462cfb1b34a16b5"},
 ]
 seed-isort-config = [
     {file = "seed_isort_config-2.2.0-py2.py3-none-any.whl", hash = "sha256:8601fb715a5a4aac39256bbf73c2da6a81f964da9c9d9897ab9074db3663526f"},
@@ -1279,8 +1262,8 @@ tomli = [
     {file = "tomli-1.2.3.tar.gz", hash = "sha256:05b6166bff487dc068d322585c7ea4ef78deed501cc124060e0f238e89a9231f"},
 ]
 tox = [
-    {file = "tox-3.24.4-py2.py3-none-any.whl", hash = "sha256:5e274227a53dc9ef856767c21867377ba395992549f02ce55eb549f9fb9a8d10"},
-    {file = "tox-3.24.4.tar.gz", hash = "sha256:c30b57fa2477f1fb7c36aa1d83292d5c2336cd0018119e1b1c17340e2c2708ca"},
+    {file = "tox-3.24.5-py2.py3-none-any.whl", hash = "sha256:be3362472a33094bce26727f5f771ca0facf6dafa217f65875314e9a6600c95c"},
+    {file = "tox-3.24.5.tar.gz", hash = "sha256:67e0e32c90e278251fea45b696d0fef3879089ccbe979b0c556d35d5a70e2993"},
 ]
 typing-extensions = [
     {file = "typing_extensions-4.0.1-py3-none-any.whl", hash = "sha256:7f001e5ac290a0c0401508864c7ec868be4e701886d5b573a9528ed3973d9d3b"},
@@ -1291,8 +1274,8 @@ urllib3 = [
     {file = "urllib3-1.26.7.tar.gz", hash = "sha256:4987c65554f7a2dbf30c18fd48778ef124af6fab771a377103da0585e2336ece"},
 ]
 virtualenv = [
-    {file = "virtualenv-20.10.0-py2.py3-none-any.whl", hash = "sha256:4b02e52a624336eece99c96e3ab7111f469c24ba226a53ec474e8e787b365814"},
-    {file = "virtualenv-20.10.0.tar.gz", hash = "sha256:576d05b46eace16a9c348085f7d0dc8ef28713a2cabaa1cf0aea41e8f12c9218"},
+    {file = "virtualenv-20.13.0-py2.py3-none-any.whl", hash = "sha256:339f16c4a86b44240ba7223d0f93a7887c3ca04b5f9c8129da7958447d079b09"},
+    {file = "virtualenv-20.13.0.tar.gz", hash = "sha256:d8458cf8d59d0ea495ad9b34c2599487f8a7772d796f9910858376d1600dd2dd"},
 ]
 wrapt = [
     {file = "wrapt-1.13.3-cp27-cp27m-macosx_10_9_x86_64.whl", hash = "sha256:e05e60ff3b2b0342153be4d1b597bbcfd8330890056b9619f4ad6b8d5c96a81a"},
diff --git a/tox.ini b/tox.ini
index c4ac41c..f8d8038 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 isolated_build = true
-envlist = py38, py39
+envlist = py38, py39, py310
 
 [testenv]
 whitelist_externals = poetry