def valid_GC(x):
x = float(x)<EOL>if x < <NUM_LIT:0.0> or x > <NUM_LIT:1.0>:<EOL><INDENT>raise ArgumentTypeError("<STR_LIT>".format(x))<EOL><DEDENT>return x<EOL>
type function for argparse to check GC values.

    Check if the supplied value for minGC and maxGC is a valid input, being between 0 and 1