def METHOD_NAME(optparser):
    """Validate options from a OptParser object.
    Return: Validated options object.
    """
    (options,args) = optparser.parse_args()
    if not (options.chain and options.protId and options.mutPos and options.aminoType):
        optparser.print_help()
        sys.exit(1)
    id, chain = getPDBIdandChain(options.protId)
    if not (id and chain):
        print "NO PDB ID"
        sys.exit(1)
    options.chain = chain
    options.protId = id
    return options