fix import order, None type annotations

Author: drew-heenan

pandas/core/generic.py

@@ -7,6 +7,7 @@
 import operator
 import pickle
 from textwrap import dedent
+from typing import Dict, Union
 import warnings
 import weakref
 
@@ -2918,7 +2919,8 @@ def to_latex(self, buf=None, columns=None, col_space=None, header=True,
 
     def to_csv(self, path_or_buf=None, sep=",", na_rep='', float_format=None,
                columns=None, header=True, index=True, index_label=None,
-               mode='w', encoding=None, compression='infer', quoting=None,
+               mode='w', encoding=None,
+               compression: Union[str, Dict, None] = 'infer', quoting=None,
                quotechar='"', line_terminator=None, chunksize=None,
                tupleize_cols=None, date_format=None, doublequote=True,
                escapechar=None, decimal='.'):

pandas/io/common.py

@@ -9,13 +9,13 @@
 import lzma
 import mmap
 import os
+from typing import (Dict, Union)
 from urllib.error import URLError  # noqa
 from urllib.parse import (  # noqa
     urlencode, urljoin, urlparse as parse_url, uses_netloc, uses_params,
     uses_relative)
 from urllib.request import pathname2url, urlopen
 import zipfile
-from typing import Dict
 
 import pandas.compat as compat
 from pandas.errors import (  # noqa
@@ -234,7 +234,7 @@ def file_path_to_url(path):
 }
 
 
-def _get_compression_method(compression: (str, Dict)):
+def _get_compression_method(compression: Union[str, Dict, None]):
     """
     Simplifies a compression argument to a compression method string and
     a dict containing additional arguments.
@@ -247,14 +247,14 @@ def _get_compression_method(compression: (str, Dict)):
 
     Returns
     -------
-    tuple of ({compression method}, str
+    tuple of ({compression method}, any
               {compression arguments}, dict)
 
     Raises
     ------
     ValueError on dict missing 'method' key
     """
-    compression_args = {}
+    compression_args = {}  # type: Dict
     # Handle dict
     if isinstance(compression, dict):
         compression_args = compression.copy()
@@ -331,8 +331,9 @@ def _infer_compression(filepath_or_buffer, compression):
     raise ValueError(msg)
 
 
-def _get_handle(path_or_buf, mode, encoding=None, compression=None,
-                memory_map=False, is_text=True):
+def _get_handle(path_or_buf, mode, encoding=None,
+                compression: Union[str, Dict, None] = None, memory_map=False,
+                is_text=True):
     """
     Get file handle for given path/buffer and mode.
 
@@ -480,7 +481,7 @@ class BytesZipFile(zipfile.ZipFile, BytesIO):  # type: ignore
     """
     # GH 17778
     def __init__(self, file, mode, compression=zipfile.ZIP_DEFLATED,
-                 arcname: (str, zipfile.ZipInfo) = None, **kwargs):
+                 arcname: Union[str, zipfile.ZipInfo, None] = None, **kwargs):
         if mode in ['wb', 'rb']:
             mode = mode.replace('b', '')
         self.arcname = arcname

pandas/io/formats/csvs.py

@@ -6,9 +6,9 @@
 import csv as csvlib
 from io import StringIO
 import os
+from typing import Dict, Union
 import warnings
 from zipfile import ZipFile
-from typing import Dict
 
 import numpy as np
 
@@ -19,16 +19,16 @@
 from pandas.core.dtypes.missing import notna
 
 from pandas.io.common import (
-    UnicodeWriter, _get_handle, _infer_compression, get_filepath_or_buffer,
-    _get_compression_method)
+    UnicodeWriter, _get_compression_method, _get_handle, _infer_compression,
+    get_filepath_or_buffer)
 
 
 class CSVFormatter(object):
 
     def __init__(self, obj, path_or_buf=None, sep=",", na_rep='',
                  float_format=None, cols=None, header=True, index=True,
                  index_label=None, mode='w', nanRep=None, encoding=None,
-                 compression: (str, Dict) = 'infer', quoting=None,
+                 compression: Union[str, Dict, None] = 'infer', quoting=None,
                  line_terminator='\n', chunksize=None, tupleize_cols=False,
                  quotechar='"', date_format=None, doublequote=True,
                  escapechar=None, decimal='.'):