@staticmethod
def is_a_command(command: str) ->bool:
    """Checks if a string is an "A" command.

        Args:
            command: a string. Examples: ""@2", ""D=A".

        Returns:
            A boolean. True, or False
        """
    first_char = command[0]
    if first_char == '@':
        return True
    return False
