[refactor] Improve performance of flatten dict function (#2896)

[refactor] Replace redundant `MutableMapping` type into `dict`

pkgs/aimstack/asp/boards/audios.py

@@ -1,4 +1,3 @@
-from collections.abc import MutableMapping
 from asp import AudioSequence
 
 audios = AudioSequence.filter()
@@ -9,7 +8,7 @@ def flatten(dictionary, parent_key='', separator='.'):
     items = []
     for key, value in dictionary.items():
         new_key = parent_key + separator + key if parent_key else key
-        if isinstance(value, MutableMapping):
+        if isinstance(value, dict):
             items.extend(flatten(value, new_key, separator=separator).items())
         else:
             items.append((new_key, value))

pkgs/aimstack/asp/boards/run.py

@@ -1,6 +1,5 @@
 from asp import Run, Metric
 from itertools import groupby
-from collections.abc import MutableMapping
 import math
 
 if 'hash' in session_state:
@@ -30,7 +29,7 @@ def flatten(dictionary, parent_key='', separator='.'):
     flattened = {}
     for key, value in dictionary.items():
         new_key = f"{parent_key}{separator}{key}" if parent_key else key
-        if isinstance(value, MutableMapping):
+        if isinstance(value, dict):
             flattened.update(flatten(value, new_key, separator=separator))
         else:
             flattened[new_key] = value

pkgs/aimstack/asp/boards/runs.py

@@ -1,5 +1,4 @@
 from asp import Run
-from collections.abc import MutableMapping
 
 form = ui.form('Search')
 
@@ -12,7 +11,7 @@ def flatten(dictionary, parent_key='', separator='.'):
     flattened = {}
     for key, value in dictionary.items():
         new_key = f"{parent_key}{separator}{key}" if parent_key else key
-        if isinstance(value, MutableMapping):
+        if isinstance(value, dict):
             flattened.update(flatten(value, new_key, separator=separator))
         else:
             flattened[new_key] = value