code: def mapper(schema):
      return VariableFeatureMapper(schema)
  
imports: from collections import OrderedDict
  import pytest
  from causalnex.structure import StructureModel
  from causalnex.structure.categorical_variable_mapper import VariableFeatureMapper, validate_schema
label_desc: Use image node_id 2 for calling a global function with example usage: mapper(schema) and returns: VariableFeatureMapper