code: def test_sigmoid_expr():
      expr = ast.SigmoidExpr(ast.NumVal(2.0))
  
      expected_code = """
  fn score(input: Vec<f64>) -> f64 {
      sigmoid(2.0_f64)
  }
  fn sigmoid(x: f64) -> f64 {
      if x < 0.0_f64 {
          let z: f64 = x.exp();
          return z / (1.0_f64 + z);
      }
      1.0_f64 / (1.0_f64 + (-x).exp())
  }
  """
  
      interpreter = RustInterpreter()
      assert_code_equal(interpreter.interpret(expr), expected_code)
  
imports: from itertools import product
  import pytest
  from m2cgen import ast
  from m2cgen.interpreters import RustInterpreter
  from tests.utils import assert_code_equal
label_desc: Use image node_id 19 for calling a global function with example usage: test_sigmoid_expr() without return types