docs: def validate(self, val):
          """
          Validates that the val is in the list of values for this Enum.
  
          Returns two element tuple: (bool, string)
  
          - `bool` - True if valid, False if not
          - `string` - Description of validation error, or None if valid
  
          :Parameters:
            val
              Value to validate.  Should be a string.
          """
          if val in self.values:
              return True, None
          else:
              return False, "'%s' is not in enum: %s" % (val, str(self.values))