docs: def check_ip(original_ip):
      '''
      Checks the format of an IP address and returns it if it is correct. Otherwise it returns None.
      ''' 
      ip = original_ip.strip()
      parts = ip.split('.')
      if len(parts) != 4:
          return None
      for p in parts:
          try:
              p = int(p)
              if (p < 0) or (p > 255):
                  return None
          except:
              return None
      return ip