Arm backend: Add docstrings to init and arm_quantizer_utils in quantizer (pytorch#14375)

Signed-off-by: Sebastian Larsson <[email protected]>

Author: Sebastian-Larsson

backends/arm/quantizer/__init__.py

@@ -2,7 +2,12 @@
 #
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
+"""Expose quantizer APIs and load optional quantized kernels.
 
+Import the public quantizer classes and configuration helpers for Arm
+backends. Attempt to load portable and quantized libraries; fall back to a
+log message if unavailable.
+"""
 
 from .quantization_config import QuantizationConfig  # noqa  # usort: skip
 from .arm_quantizer import (  # noqa

backends/arm/quantizer/arm_quantizer_utils.py

@@ -6,10 +6,12 @@
 # LICENSE file in the root directory of this source tree.
 
 # pyre-unsafe
+"""Provide utilities for quantization annotations.
 
-#
-# Utility functions for TOSAQuantizer
-#
+Use these helpers to check and mark annotation state when working with
+``QuantizationAnnotation`` entries in FX node metadata.
+
+"""
 
 from typing import cast
 
@@ -20,15 +22,31 @@
 
 
 def is_annotated(node: Node) -> bool:
-    """Given a node return whether the node is annotated."""
+    """Return True if the node is annotated.
+
+    Args:
+        node (Node): FX node to inspect.
+
+    Returns:
+        bool: True if ``Q_ANNOTATION_KEY`` exists and ``_annotated`` is set.
+
+    """
     return (
         Q_ANNOTATION_KEY in node.meta
         and cast(QuantizationAnnotation, node.meta[Q_ANNOTATION_KEY])._annotated
     )
 
 
 def is_output_annotated(node: Node) -> bool:
-    """Given a node, return whether the output of the node is annotated."""
+    """Return True if the node's output is annotated.
+
+    Args:
+        node (Node): FX node to inspect.
+
+    Returns:
+        bool: True if annotated and an output qspec is present.
+
+    """
     if Q_ANNOTATION_KEY in node.meta:
         annotation = cast(QuantizationAnnotation, node.meta[Q_ANNOTATION_KEY])
         return annotation._annotated and annotation.output_qspec is not None
@@ -37,8 +55,14 @@ def is_output_annotated(node: Node) -> bool:
 
 
 def mark_node_as_annotated(node: Node) -> None:
-    """Marks node as annotated. If needed, an empty  QuantizationAnnotation is added
-    to the quantization_annotation node meta entry.
+    """Mark a node as annotated.
+
+    Create an empty ``QuantizationAnnotation`` on the node when missing and set
+    its ``_annotated`` flag to True.
+
+    Args:
+        node (Node): FX node to update.
+
     """
     if Q_ANNOTATION_KEY not in node.meta:
         node.meta[Q_ANNOTATION_KEY] = QuantizationAnnotation()