code: def cmd_reverse_lookup(command_name):
      '''returns 0 if key not found'''
      for key, value in miss_cmds.items():
          if (value.upper() == command_name.upper()):
              return key
      return f cmd_reverse_lookup(command_name):
      '''returns 0 if key not found'''
      for key, value in miss_cmds.items():
          if (value.upper() == command_name.upper()):
              return key
      return 0
docs: returns 0 if key not found