code: def parse_charset(charset):
      
      import re
      regex = r'(\w-\w)'
      pat = re.compile(regex)
      found = pat.findall(charset)
      result = ''
      if found:
          for element in found:
              for char in char_range(element[0], element[-1]):
                  result += char
          return result
      return charset
docs: Finds out whether there are intervals to expand and
      creates the charset