code: def validipaddr(address):
      
      try:
          octets = address.split('.')
          if len(octets) != 4:
              return False
          for x in octets:
              if not (0 <= int(x) <= 255):
                  return False
      except ValueError:
          return False
      return True
docs: Returns True if `address` is a valid IPv4 address.
      
          >>> validipaddr('192.168.1.1')
          True
          >>> validipaddr('192.168.1.800')
          False
          >>> validipaddr('192.168.1')
          False