from __future__ import annotations


def is_command(message: str | None) -> bool:
    return bool(message and message.startswith("/"))


def find_command_argument(message: str | None) -> str | None:
    """Finds the value of argument in command message text.
    Get string from Message.text.

    Example:
    >>> find_command_argument("/start referrer")
    "referrer"
    >>> find_command_argument("/start")
    None
    >>> find_command_argument("hi! it's me")
    None

    """
    if not is_command(message):
        return None

    return str(message).split()[1] if " " in str(message) else None