- mypy, flake8, pre-commit, pipenv

- small refactoring
- tests
- lib is now doesn't rely on any dataframe framework

.pre-commit-config.yaml

@@ -0,0 +1,18 @@
+repos:
+-   repo: https://github.com/ambv/black
+    rev: stable
+    hooks:
+    - id: black
+      args: ['--line-length', '120']
+-   repo: https://github.com/pre-commit/mirrors-mypy
+    rev: 'v0.780'  # Use the sha / tag you want to point at
+    hooks:
+    - id: mypy
+      args: ['--config-file', 'mypy.ini']
+-   repo: https://gitlab.com/pycqa/flake8
+    rev: 3.8.2
+    hooks:
+    - id: flake8
+      args: ['--config', 'flake8.cfg']
+      additional_dependencies:
+        - isort<5  # https://github.com/gforcada/flake8-isort/issues/88

Pipfile

@@ -0,0 +1,15 @@
+[[source]]
+name = "pypi"
+url = "https://pypi.org/simple"
+verify_ssl = true
+
+[dev-packages]
+black = "==19.10b0"
+flake8 = "*"
+mypy = "*"
+pre-commit = "*"
+
+[packages]
+
+[requires]
+python_version = "3.7"

df_and_order/common.py

@@ -0,0 +1,3 @@
+from typing import Any
+
+DF_TYPE = Any

df_and_order/df_cache.py

@@ -1,7 +1,8 @@
-import pandas as pd
 from abc import ABC, abstractmethod
 from typing import Optional
 
+from df_and_order.common import DF_TYPE
+
 
 class DfCache(ABC):
     """
@@ -18,26 +19,29 @@ class DfCache(ABC):
     load_kwargs: dict
         Custom kwargs for load method you may want to pass to your implementation.
     """
-    def __init__(self,
-                 save_args: Optional[list] = None,
-                 save_kwargs: Optional[dict] = None,
-                 load_args: Optional[list] = None,
-                 load_kwargs: Optional[dict] = None):
+
+    def __init__(
+        self,
+        save_args: Optional[list] = None,
+        save_kwargs: Optional[dict] = None,
+        load_args: Optional[list] = None,
+        load_kwargs: Optional[dict] = None,
+    ):
         self._save_args = save_args or []
         self._save_kwargs = save_kwargs or {}
         self._load_args = load_args or []
         self._load_kwargs = load_kwargs or {}
 
-    def save(self, df: pd.DataFrame, path: str):
-        self._save(df=df, path=path, *self._save_args, **self._save_kwargs)
+    def save(self, df: DF_TYPE, path: str):
+        self._save(df=df, path=path, *self._save_args, **self._save_kwargs)  # type: ignore
 
-    def load(self, path: str) -> pd.DataFrame:
-        return self._load(path=path, *self._load_args, **self._load_kwargs)
+    def load(self, path: str) -> DF_TYPE:
+        return self._load(path=path, *self._load_args, **self._load_kwargs)  # type: ignore
 
     @abstractmethod
-    def _save(self, df: pd.DataFrame, path: str, *args, **kwargs):
+    def _save(self, df: DF_TYPE, path: str, *args, **kwargs):
         pass
 
     @abstractmethod
-    def _load(self, path: str, *args, **kwargs) -> pd.DataFrame:
+    def _load(self, path: str, *args, **kwargs) -> DF_TYPE:
         pass