code: def make_key_source(size):
      return {i: string.ascii_lowercase[i] for i in range(size)}
  
imports: from dash.dependencies import Input
  from dash._grouping import flatten_grouping, make_grouping_by_index, grouping_len, map_grouping, make_grouping_by_key, validate_grouping, SchemaTypeValidationError, SchemaLengthValidationError, SchemaKeysValidationError
  from fixtures import scalar_grouping_size, list_grouping_size, dict_grouping_size, mixed_grouping_size
  import string
  import pytest
label_desc: Use image node_id 16 for calling a global function with example usage: make_key_source(size) and returns: unknown