def __get_parsing_plan_for_multifile_children(self, obj_on_fs: PersistedObject, desired_type: Type[Any],
                                                  children_on_fs: Dict[str, PersistedObject], logger: Logger) \
            -> Dict[str, Any]:
        """
        Simply inspects the required type to find the names and types of its constructor arguments.
        Then relies on the inner ParserFinder to parse each of them.

        :param obj_on_fs:
        :param desired_type:
        :param children_on_fs:
        :param logger:
        :return:
        """

        # -- (a) collect pep-484 information in the class constructor to be able to understand what is required
        constructor_args_types_and_opt = get_constructor_attributes_types(desired_type)

        # -- (b) plan to parse each attribute required by the constructor
        children_plan = dict()  # results will be put in this object

        # --use sorting in order to lead to reproducible results in case of multiple errors
        for attribute_name, att_desc in sorted(constructor_args_types_and_opt.items()):
            attribute_is_mandatory = att_desc[1]
            attribute_type = att_desc[0]

            # get the child
            if attribute_name in children_on_fs.keys():
                child_on_fs = children_on_fs[attribute_name]

                # find a parser
                t, parser_found = self.parser_finder.build_parser_for_fileobject_and_desiredtype(child_on_fs,
                                                                                                 attribute_type,
                                                                                                 logger=logger)
                # create a parsing plan
                children_plan[attribute_name] = parser_found.create_parsing_plan(t, child_on_fs,
                                                                                 logger=logger, _main_call=False)
            else:
                if attribute_is_mandatory:
                    raise MissingMandatoryAttributeFiles.create(obj_on_fs, desired_type, attribute_name)
                else:
                    # we don't care : optional attribute
                    # dont use warning since it does not show up nicely
                    msg = 'NOT FOUND - This optional constructor attribute for type ' \
                          + get_pretty_type_str(desired_type) + ' was not found on file system, but this may be normal'\
                          ' - this message is displayed \'just in case\'.'
                    if logger.isEnabledFor(DEBUG):
                        logger.warning('(B) ' + obj_on_fs.get_pretty_child_location(attribute_name,
                                                                                    blank_parent_part=True) + ': '
                                       + msg)
                    else:
                        logger.warning('WARNING parsing [{loc}] as a [{typ}]: optional constructor attribute [{att}] '
                                       'not found on file system. This may be normal - this message is displayed \'just'
                                       ' in case\'.'.format(
                            loc=obj_on_fs.get_pretty_location(blank_parent_part=False, append_file_ext=False),
                            typ=get_pretty_type_str(desired_type),
                            att=attribute_name))

        return children_plan