import base64


def multibase_b64decode(data):
    """
    Follow forge's base64 urlsafe encode convention to decode string

    Args:
        data(string): encoded string

    Returns: bytes

    Examples:
        >>> multibase_b64decode('aGVsbG8')
        b'hello'
    """

    if isinstance(data, str):
        data = data.encode()
    return base64.urlsafe_b64decode(
            (data + b'=' * (-len(data) % 4)))