code: def test_required_funs_without_fallbacks():
      expr = ast.LogExpr(ast.PowExpr(ast.NumVal(1.0), ast.NumVal(-2.0)))
  
      interpreter = PythonInterpreter()
  
      interpreter.power_function_name = NotImplemented
      with pytest.raises(
          NotImplementedError, match="Power function is not provided"
      ):
          interpreter.interpret(expr)
  
      interpreter.logarithm_function_name = NotImplemented
      with pytest.raises(
          NotImplementedError,
          match="Logarithm function is not provided",
      ):
          interpreter.interpret(expr)
  
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 1 for calling a global function with example usage: test_required_funs_without_fallbacks() without return types