def _parse_variable_name(line):
    """
    :param line: Line in the file
    :returns: The variable name being assigned.

    >>> line = 'X = [1];'
    >>> _parse_variable_name(line)
    X

    """
    rhs = line.split('=')[0].strip()
    if rhs.find('(') >= 0:
        rhs = rhs[:rhs.find('(')]
    return rhs