+
+def is_hex(s, *length_args):
+ """is_hex(s[, length[, max_length]]) -> boolean
+
+ Return True if s is a string of hexadecimal digits.
+ If one length argument is given, the string must contain exactly
+ that number of digits.
+ If two length arguments are given, the string must contain a number of
+ digits between those two lengths, inclusive.
+ Return False otherwise.
+ """
+ num_length_args = len(length_args)
+ if num_length_args > 2:
+ raise ArgumentError("is_hex accepts up to 3 arguments ({} given)".
+ format(1 + num_length_args))
+ elif num_length_args == 2:
+ good_len = (length_args[0] <= len(s) <= length_args[1])
+ elif num_length_args == 1:
+ good_len = (len(s) == length_args[0])
+ else:
+ good_len = True
+ return bool(good_len and HEX_RE.match(s))