code: def _validate_alias_name(alias_name):
      
      if not alias_name:
          raise CLIError(EMPTY_ALIAS_ERROR)
  
      if not re.match('^[a-zA-Z]', alias_name):
          raise CLIError(INVALID_STARTING_CHAR_ERROR.format(alias_name[0]))
docs: Check if the alias name is valid.
  
      Args:
          alias_name: The name of the alias to validate.