code: def to_python(self, value):
          
          # pylint: disable=newstyle
          value = super(TimeZoneField, self).to_python(value)
  
          if not value:
              return value
  
          try:
              return pytz.timezone(str(value))
          except pytz.UnknownTimeZoneError:
              raise ValidationError(
                  message=self.error_messages['invalid'],
                  code='invalid',
                  params={'value': value}
              )
docs: Returns a datetime.tzinfo instance for the value.