How to use the pbxproj.pbxextensions.ProjectFiles.TreeType function in pbxproj

return []

        file_ref, abs_path, path, tree, expected_build_phase = self._add_file_reference(path, parent, tree, force,
                                                                                        file_options)
        if path is None or tree is None:
            return None

        # no need to create the build_files, done
        if not file_options.create_build_files:
            return results

        # create build_files for the targets
        results.extend(self._create_build_files(file_ref, target_name, expected_build_phase, file_options))

        # special case for the frameworks and libraries to update the search paths
        if tree != TreeType.SOURCE_ROOT or abs_path is None:
            return results

        # the path is absolute and it's outside the scope of the project for linking purposes
        library_path = os.path.join(u'$(SRCROOT)', os.path.split(file_ref.path)[0])
        if os.path.isfile(abs_path):
            self.add_library_search_paths([library_path], recursive=False)
        else:
            self.add_framework_search_paths([library_path, u'$(inherited)'], recursive=False)

        return results

def options(cls):
        return [TreeType.SOURCE_ROOT, TreeType.SDKROOT, TreeType.GROUP, TreeType.ABSOLUTE,
                TreeType.DEVELOPER_DIR, TreeType.BUILT_PRODUCTS_DIR]

def options(cls):
        return [TreeType.SOURCE_ROOT, TreeType.SDKROOT, TreeType.GROUP, TreeType.ABSOLUTE,
                TreeType.DEVELOPER_DIR, TreeType.BUILT_PRODUCTS_DIR]

def __init__(self, parser):
        file_parser = parser.add_parser(u'file', help=u'Manipulate files in the project')
        # common parameters
        standard_parameters(file_parser)
        file_parser.add_argument(u'path', help=u'file path to be added to the project')
        file_parser.add_argument(u'--tree', choices=TreeType.options(), default=TreeType.SOURCE_ROOT,
                                 help=u'tree relative to the origin of the file to be added.')

        # remove parameters
        remove_parser = file_parser.add_argument_group(u'Remove file options')
        remove_parser.add_argument(u'--delete', u'-D', action=u'store_true', help=u'')

        # add parameters
        add_parser = file_parser.add_argument_group(u'Add file options')
        add_parser.add_argument(u'--weak', u'-w', action=u'store_true', help=u'link framework weakly.')
        add_parser.add_argument(u'--no-embed', u'-E', action=u'store_false', dest=u'embed',
                                help=u'do not embed framework on the application')
        add_parser.add_argument(u'--sign-on-copy', u'-csoc', action=u'store_true', dest=u'code_sign_on_copy',
                                help=u'code sign frameworks when copied to the application.')
        add_parser.add_argument(u'--ignore-unknown-types', u'-i', action=u'store_true', dest=u'ignore_unknown_types',
                                help=u'ignore unknown types and add the file regardless.')
        add_parser.add_argument(u'--no-create-build-files', u'-C', action=u'store_false', dest=u'create_build_files',

    def add_project(self, path, parent=None, tree=TreeType.GROUP, target_name=None, force=True, file_options=FileOptions()):
        """
        Adds another Xcode project into this project. Allows to use the products generated from the given project into
        this project during compilation time. Optional: it can add the products into the different sections: frameworks
        and bundles.

        :param path: Path to the .xcodeproj file
        :param parent: Parent group to be added under
        :param tree: Tree where the path is relative to
        :param target_name: Target name or list of target names where the file should be added (none for every target)
        :param force: Add the file without checking if the file already exists
        :param file_options: FileOptions object to be used during the addition of the file to the project.
        :return: list of PBXReferenceProxy objects that can be used to create the PBXBuildFile phases.
        """
        results = []
        # if it's not forced to add the file stop if the file already exists.
        if not force:

def get_attributes(self, file_ref, build_phase):
        if file_ref.get_file_type() != u'wrapper.framework' and file_ref.get_file_type() != u'sourcecode.c.h':
            return None

        attributes = None
        if build_phase.isa == u'PBXFrameworksBuildPhase':
            attributes = [u'Weak'] if self.weak else None

        if build_phase.isa == u'PBXCopyFilesBuildPhase' and \
                file_ref.sourceTree != TreeType.SDKROOT and \
                self.code_sign_on_copy:
            if attributes is None:
                attributes = []
            attributes += [u'CodeSignOnCopy', u'RemoveHeadersOnCopy']

        if build_phase.isa == u'PBXHeadersBuildPhase':
            attributes = [self.header_scope] if self.header_scope != HeaderScope.PROJECT else None

        return attributes