support timezone data in iso date strings

The latest release of the isodate package (0.7.2) doesn’t handle
timezone information for dates. While this is indeed not valid according
to the ISO specs we want to handle it anway.

At a workaround by stripping the timezone data ourselves

src/zeep/xsd/types/builtins.py

@@ -210,7 +210,19 @@ def xmlvalue(self, value):
 
     @treat_whitespace("collapse")
     def pythonvalue(self, value):
-        return isodate.parse_date(value)
+        try:
+            return isodate.parse_date(value)
+        except isodate.ISO8601Error:
+            # Recent versions of isodate don't support timezone in date's. This
+            # is not really ISO8601 compliant anway, but we should try to handle
+            # it. This is a hack to support this.
+            if "+" in value:
+                value = value.split("+")[0]
+                return isodate.parse_date(value)
+            if "Z" in value:
+                value = value.split("Z")[0]
+                return isodate.parse_date(value)
+            raise
 
 
 class gYearMonth(BuiltinType):