This converts the supplied hexadecimal string s back to a normal string. The converted string may contain binary zeroes.
eg.
print (utils.fromhex ("4E69636B2047616D6D6F6E")) --> Nick Gammon
The supplied string may contain 'space' characters (0x09 – 0x0D or 0x20) which are ignored, otherwise if it contains characters other than A-F, a-f or 0-9 this function raises an error. If the number of characters is odd then the last character is treated as the low-order nibble of the final byte. eg.
a = utils.fromhex ("ABC") --> same as utils.fromhex ("AB0C")
Note that "spaces are ignored" means that a sequence like "A B C D" is treated as the same as "ABCD" not "0A 0B 0C 0D".