Fix parsing datetime containing timezone information for python 3.6

Required method for parsing datetime 'fromisoformat' was added in
python version 3.7, thus backport of that method was added to
the requirements list.

Also '%z' directive was updated in python 3.7 to support timezone
information in the "+xx:xx" or "Z" format. Hence, changes were made to
allow compatibility of these notations in python 3.6 and lower.

https://docs.python.org/3/library/datetime.html

Author: mamiksik

CHANGELOG.md

@@ -27,6 +27,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   unknown type/member - Martin Miksik
 - Race condition in `test_types_repository_separation` - Martin Miksik
 - Import error while using python version prior to 3.7 - Martin Miksik
+- Parsing datetime containing timezone information for python 3.6 and lower - Martin Miksik
 
 ## [1.3.0]
 

pyodata/v4/type_traits.py

@@ -1,5 +1,6 @@
 """ Type traits for types specific to the ODATA V4"""
 
+import sys
 import datetime
 
 # In case you want to use geojson types. You have to install pip package 'geojson'
@@ -14,6 +15,10 @@
 from pyodata.exceptions import PyODataModelError, PyODataException
 from pyodata.model.type_traits import TypTraits
 
+if sys.version_info < (3, 7):
+    from backports.datetime_fromisoformat import MonkeyPatch
+    MonkeyPatch.patch_fromisoformat()
+
 
 class EdmDoubleQuotesEncapsulatedTypTraits(TypTraits):
     """Good for all types which are encapsulated in double quotes"""
@@ -218,6 +223,13 @@ def from_literal(self, value: str):
 
         value = super().from_literal(value)
 
+        if sys.version_info < (3, 7):
+            if value[len(value) - 3] == ':':
+                value = value[:len(value) - 3] + value[-2:]
+
+            if value[len(value) - 1] == 'Z':
+                value = value[:len(value) - 1] + "+0000"
+
         try:
             value = datetime.datetime.strptime(value, '%Y-%m-%dT%H:%M:%S.%f%z')
         except ValueError:

requirements.txt

@@ -1 +1,2 @@
 lxml>=3.7.3
+backports-datetime-fromisoformat>=1.0