def METHOD_NAME(self):
    # Create a blockstore content library
    library = self._create_library(slug="testlib1_import", title="A Test Library", description="Testing XBlocks")
    # Create a unit block with an HTML block in it.
    unit_block_id = self._add_block_to_library(library["id"], "unit", "unit1")["id"]
    html_block_id = self._add_block_to_library(library["id"], "html", "html1", parent_block=unit_block_id)["id"]
    html_block = load_block(UsageKey.from_string(html_block_id), self.user)
    # Add assets and content to the HTML block
    self._set_library_block_asset(html_block_id, "test.txt", b"data", expect_response=200)
    self._set_library_block_olx(html_block_id, '<html><a href="/static/test.txt">Hello world</a></html>')
    # Create a modulestore course
    course = CourseFactory.create(modulestore=self.store, user_id=self.user.id)
    CourseInstructorRole(course.id).add_users(self.user)
    # Add Source from library block to the course
    sourced_block = self.make_block("library_sourced", course, user_id=self.user.id)
    # Import the unit block from the library to the course
    self.tools.import_from_blockstore(sourced_block, [unit_block_id])
    # Verify imported block with its children
    assert len(sourced_block.children) == 1
    assert sourced_block.children[0].category == 'unit'
    imported_unit_block = self.store.get_item(sourced_block.children[0])
    assert len(imported_unit_block.children) == 1
    assert imported_unit_block.children[0].category == 'html'
    imported_html_block = self.store.get_item(imported_unit_block.children[0])
    assert 'Hello world' in imported_html_block.data
    # Check that assets were imported and static paths were modified after importing
    assets = library_api.get_library_block_static_asset_files(html_block.scope_ids.usage_id)
    assert len(assets) == 1
    assert assets[0].url in imported_html_block.data
    # Check that reimporting updates the target block
    self._set_library_block_olx(html_block_id, '<html><a href="/static/test.txt">Foo bar</a></html>')
    self.tools.import_from_blockstore(sourced_block, [unit_block_id])
    assert len(sourced_block.children) == 1
    imported_unit_block = self.store.get_item(sourced_block.children[0])
    assert len(imported_unit_block.children) == 1
    imported_html_block = self.store.get_item(imported_unit_block.children[0])
    assert 'Hello world' not in imported_html_block.data
    assert 'Foo bar' in imported_html_block.data