code: def from_iso_permissive(datestring, use_dateutil=True):
          
          dateutil_available = False
          try:
              from dateutil import parser
              dateutil_available = True
          except ImportError:
              dateutil_available = False
              import datetime
  
          # Use dateutil's parser if possible
          if dateutil_available and use_dateutil:
              return parser.parse(datestring)
          else:
              # Strip off timezone info.
              return datetime.datetime.strptime(datestring[:19],
                                                '%Y-%m-%dT%H:%M:%S')
docs: Parse an ISO8601-formatted datetime and return a datetime object.
  
          Inspired by the marshmallow.utils.from_iso function, but also accepts
          datestrings that don't contain the time.