def is_member(musicians, musician_name):
    """Return true if named musician is in musician list;
    otherwise return false.

    Parameters:
        musicians (list): list of musicians and their instruments
        musician_name (str): musician name

    Returns:
        bool: True if match is made; otherwise False.

    """
    i = 0 # counter

    while i < len(musicians): # guard against infinite loop
        musician = musicians[i].split(', ')[0].lower()
        if musician_name.lower() == musician:
            return True # preferable to break statement
        i += 1 # MUST INCREMENT

    return False