Added function for inverting mapping

Author: cnheider

warg/__init__.py

@@ -1,7 +1,7 @@
 __project__ = "Warg"
 
 __author__ = "Christian Heider Lindbjerg"
-__version__ = "1.5.2"
+__version__ = "1.5.3"
 __doc__ = r"""
 Created on 27/04/2019
 

warg/data_structures/mappings.py

@@ -1,7 +1,7 @@
 from collections import defaultdict
 
 import logging
-from typing import Callable, Dict, Hashable, Iterable, Mapping, MutableMapping
+from typing import Any, Callable, Dict, Hashable, Iterable, List, Mapping, MutableMapping
 
 _logger = logging.getLogger(__name__)
 __all__ = [
@@ -12,6 +12,7 @@
     "pivot_dict",
     "to_dict",
     "nested_dict",
+    "invert_mapping_list",
 ]
 
 
@@ -87,6 +88,22 @@ def invert_dict(d: Mapping) -> Dict:  # TODO: HANDLE DUPLICATE KEYS; CONVERT TO
     return {v: k for k, v in d.items()}
 
 
+def invert_mapping_list(m: Mapping[Any, Any]) -> Mapping[Any, List[Any]]:
+    """
+
+    :param m:
+    :type m:
+    :return:
+    :rtype:
+    """
+    out = defaultdict(list)
+
+    for k, v in m.items():
+        out[v].append(k)
+
+    return out
+
+
 def pivot_dict(d: Dict, key) -> Dict:  # TODO: HANDLE DUPLICATE KEYS; CONVERT TO TUPLES
     """
     pivot_key -> pivot_value

warg/datetimes.py

@@ -12,7 +12,7 @@
 DEFAULT_REPRESENTATION = "%Y-%m-%d_%H:%M:%S.%f"
 
 
-def default_datetime_repr(date: datetime, str_format: str = DEFAULT_REPRESENTATION) -> str:
+def default_datetime_repr(date: datetime.datetime, str_format: str = DEFAULT_REPRESENTATION) -> str:
     """
 
     :param date: