code: def test_sigmoid_fallback_expr():
      expr = ast.SigmoidExpr(ast.NumVal(2.0))
  
      class InterpreterWithoutSigmoid(PythonInterpreter):
          sigmoid_function_name = NotImplemented
  
          def interpret_sigmoid_expr(self, expr, **kwargs):
              return super(
                  PythonInterpreter, self
              ).interpret_sigmoid_expr(expr, **kwargs)
  
      interpreter = InterpreterWithoutSigmoid()
  
      expected_code = """
  import math
  def score(input):
      return 1.0 / (1.0 + math.exp(0.0 - 2.0))
  """
  
      assert_code_equal(interpreter.interpret(expr), expected_code)
  
file_path: m2cgen/tests/test_fallback_expressions.py
imports: import pytest
  from m2cgen import ast
  from m2cgen.interpreters import CInterpreter, PythonInterpreter
  from tests.utils import assert_code_equal
label_desc: Use image node_id 9 for calling a global function with example usage: test_sigmoid_fallback_expr() and returns: super