add sub_blocks for pipelineBlock

Author: yiyixuxu

src/diffusers/modular_pipelines/components_manager.py

@@ -229,6 +229,7 @@ class ComponentsManager:
 
     def __init__(self):
         self.components = OrderedDict()
+        # YiYi TODO: can remove once confirm we don't need this in mellon
         self.added_time = OrderedDict()  # Store when components were added
         self.collections = OrderedDict()  # collection_name -> set of component_names
         self.model_hooks = None

src/diffusers/modular_pipelines/modular_pipeline.py

@@ -353,6 +353,9 @@ def init_pipeline(
 class PipelineBlock(ModularPipelineBlocks):
     model_name = None
 
+    def __init__(self):
+        self.sub_blocks = InsertableDict()
+
     @property
     def description(self) -> str:
         """Description of the block. Must be implemented by subclasses."""
@@ -2129,6 +2132,7 @@ def update_components(self, **kwargs):
         self.register_to_config(**config_to_register)
 
     # YiYi TODO: support map for additional from_pretrained kwargs
+    # YiYi/Dhruv TODO: consolidate load_components and load_default_components?
     def load_components(self, names: Union[List[str], str], **kwargs):
         """
         Load selected components from specs.