docs: @SuppressWarnings("unchecked") @Nullable public Object resolveArgument(@NotNull String name,
        @NotNull Operation.Variables variables) {
      checkNotNull(name, "name == null");
      checkNotNull(variables, "variables == null");
      Map<String, Object> variableValues = variables.valueMap();
      Object argumentValue = arguments.get(name);
      if (argumentValue instanceof Map) {
        Map<String, Object> argumentValueMap = (Map<String, Object>) argumentValue;
        if (isArgumentValueVariableType(argumentValueMap)) {
          String variableName = argumentValueMap.get(VARIABLE_NAME_KEY).toString();
          return variableValues.get(variableName);
        } else {
          return null;
        }
      }
      return argumentValue;
    }