code: def srange(s):
      r
      try:
          return "".join(_expanded(part) for part in _reBracketExpr.parseString(s).body)
      except:
          return ""
docs: r"""Helper to easily define string ranges for use in Word construction.  Borrows
         syntax from regexp '[]' string range definitions::
            srange("[0-9]")   -> "0123456789"
            srange("[a-z]")   -> "abcdefghijklmnopqrstuvwxyz"
            srange("[a-z$_]") -> "abcdefghijklmnopqrstuvwxyz$_"
         The input string must be enclosed in []'s, and the returned string is the expanded
         character set joined into a single string.
         The values enclosed in the []'s may be::
            a single character
            an escaped character with a leading backslash (such as \- or \])
            an escaped hex character with a leading '\x' (\x21, which is a '!' character) 
              (\0x## is also supported for backwards compatibility) 
            an escaped octal character with a leading '\0' (\041, which is a '!' character)
            a range of any of the above, separated by a dash ('a-z', etc.)
            any combination of the above ('aeiouy', 'a-zA-Z0-9_$', etc.)