code: def test_sigmoid_expr():
      expr = ast.SigmoidExpr(ast.NumVal(2.0))
  
      expected_code = """
  sigmoid <- function(x) {
      if (x < 0.0) {
          z <- exp(x)
          return(z / (1.0 + z))
      }
      return(1.0 / (1.0 + exp(-x)))
  }
  score <- function(input) {
      return(sigmoid(2.0))
  }
  """
  
      interpreter = RInterpreter()
      assert_code_equal(interpreter.interpret(expr), expected_code)
  
imports: from itertools import product
  import pytest
  from m2cgen import ast
  from m2cgen.interpreters import RInterpreter
  from tests.utils import assert_code_equal
label_desc: Use image node_id 24 for calling a global function with example usage: test_sigmoid_expr() without return types