code: def namedb_state_mutation_sanity_check( opcode, op_data ):
      
  
      # sanity check:  each mutate field in the operation must be defined in op_data, even if it's null.
      missing = []
      mutate_fields = op_get_mutate_fields( opcode )
      for field in mutate_fields:
          if field not in op_data.keys():
              missing.append( field )
  
      assert len(missing) == 0, ("BUG: operation '%s' is missing the following fields: %s" % (opcode, ",".join(missing)))
      return True
docs: Make sure all mutate fields for this operation are present.
      Return True if so
      Raise exception if not