Advanced Ip filtering (#4424)

* Added IP Bans configuration

* Fixing warnings

* Added ban enabled option and unit tests

* Fixed py34 tox

* http: requested changes fix

* Requested changes fix

homeassistant/helpers/config_validation.py

@@ -1,6 +1,6 @@
 """Helpers for config validation using voluptuous."""
 from collections import OrderedDict
-from datetime import timedelta
+from datetime import timedelta, datetime as datetime_sys
 import os
 import re
 from urllib.parse import urlparse
@@ -297,6 +297,22 @@ def time(value):
     return time_val
 
 
+def datetime(value):
+    """Validate datetime."""
+    if isinstance(value, datetime_sys):
+        return value
+
+    try:
+        date_val = dt_util.parse_datetime(value)
+    except TypeError:
+        date_val = None
+
+    if date_val is None:
+        raise vol.Invalid('Invalid datetime specified: {}'.format(value))
+
+    return date_val
+
+
 def time_zone(value):
     """Validate timezone."""
     if dt_util.get_time_zone(value) is not None: