def parse_email(address):
    """
    Returns "Marco Polo", "marco@polo.com" from "Marco Polo <marco@polo.com"
    Returns "", "marco@polo.com" from "marco@polo.com"
    """
    if ' ' in address.strip():
        assert '<' in address and '>' in address, 'Invalid address structure: %s' % (
            address,)
        parts = address.split(' ')
        name = ' '.join(parts[:-1])
        address = parts[-1][1:-1]
        return name, address
    else:
        return '', address
