def convert_activity(ast):
    """Convert BEL1 activities to BEL2 act()"""

    if len(ast.args) > 1:
        log.error(f"Activity should not have more than 1 argument {ast.to_string()}")

    p_arg = ast.args[0]  # protein argument
    print("p_arg", p_arg)
    ma_arg = Function("ma", bo.spec)
    ma_arg.add_argument(StrArg(ast.name, ma_arg))
    p_arg.change_parent_fn(ma_arg)
    ast = Function("activity", bo.spec)
    p_arg.change_parent_fn(ast)
    ast.add_argument(p_arg)
    ast.add_argument(ma_arg)

    return ast