diff --git a/poetry.lock b/poetry.lock
index 8073326..4bc41e5 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -307,17 +307,17 @@ test = ["pytest (>=3.6.0)", "pytest-cov", "mock"]
 
 [[package]]
 name = "isort"
-version = "4.3.21"
+version = "5.9.3"
 description = "A Python utility / library to sort Python imports."
 category = "dev"
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
+python-versions = ">=3.6.1,<4.0"
 
 [package.extras]
-pipfile = ["pipreqs", "requirementslib"]
-pyproject = ["toml"]
-requirements = ["pipreqs", "pip-api"]
-xdg_home = ["appdirs (>=1.4.0)"]
+pipfile_deprecated_finder = ["pipreqs", "requirementslib"]
+requirements_deprecated_finder = ["pipreqs", "pip-api"]
+colors = ["colorama (>=0.4.3,<0.5.0)"]
+plugins = ["setuptools"]
 
 [[package]]
 name = "janome"
@@ -1077,7 +1077,7 @@ testing = ["pathlib2", "contextlib2", "unittest2"]
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.7"
-content-hash = "89c5b7fe627c2dcb8282085b1af16357ac0c77ee53eb65ab0336a803e98ab799"
+content-hash = "8697fcd6d4f12c7fcf2db4e2190368248b07d26ceb7acb67bc69ab5212c4aa1b"
 
 [metadata.files]
 appdirs = [
@@ -1210,8 +1210,8 @@ ipywidgets = [
     {file = "ipywidgets-7.5.1.tar.gz", hash = "sha256:e945f6e02854a74994c596d9db83444a1850c01648f1574adf144fbbabe05c97"},
 ]
 isort = [
-    {file = "isort-4.3.21-py2.py3-none-any.whl", hash = "sha256:6e811fcb295968434526407adb8796944f1988c5b65e8139058f2014cbe100fd"},
-    {file = "isort-4.3.21.tar.gz", hash = "sha256:54da7e92468955c4fceacd0c86bd0ec997b0e1ee80d97f67c35a78b719dccab1"},
+    {file = "isort-5.9.3-py3-none-any.whl", hash = "sha256:e17d6e2b81095c9db0a03a8025a957f334d6ea30b26f9ec70805411e5c7c81f2"},
+    {file = "isort-5.9.3.tar.gz", hash = "sha256:9c2ea1e62d871267b78307fe511c0838ba0da28698c5732d54e2790bf3ba9899"},
 ]
 janome = [
     {file = "Janome-0.4.1-py2.py3-none-any.whl", hash = "sha256:a650e2684e80af72f869eff17566f31dd4444f5443c4771dca1ada60cea5c251"},
diff --git a/pyproject.toml b/pyproject.toml
index 551b0c0..0881467 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,7 +18,7 @@ black = "^19.10b0"
 flake8-bugbear = "^20.1.2"
 flake8 = "^3.7.9"
 ipython = "^7.11.1"
-isort = "^4.3.21"
+isort = "^5.0.0"
 jupyter = "^1.0.0"
 mypy = "^0.761"
 pre-commit = "^1.21.0"