def add_prefix_before_line(prefix, src):
    """
        add_prefix_before_line()
        ________________________________________________________________________

        Add the string <prefix> before every line in <src>.
        ________________________________________________________________________

        ARGUMENTS:
        ▪ prefix    : (str)
        ▪ src       : (str)

        RETURNED VALUE : the expected string
    """
    res = []
    for line in src.split('\n'):
        res.append(prefix + line)
    return '\n'.join(res)
