code: public static boolean isInput(GraphQLType type) {
          GraphQLUnmodifiedType unmodifiedType = unwrapAll(type);
          return
                  unmodifiedType instanceof GraphQLScalarType
                          || unmodifiedType instanceof GraphQLEnumType
                          || unmodifiedType instanceof GraphQLInputObjectType;
      }
docs: Returns true if the given type is an input type
  
  @param type the type to check
  
  @return true if the given type is an input type