code: def test_is_extended_real():
      x = Symbol("x", extended_real=True)
      y = Symbol("y", extended_real=False)
      z = Symbol("z")
      assert is_extended_real(x)
      assert not is_extended_real(y)
      assert is_extended_real(z) is None
      assert is_extended_real(z, Q.extended_real(z))
  
file_path: sympy/sympy/assumptions/tests/test_wrapper.py
imports: from sympy.assumptions.ask import Q
  from sympy.assumptions.wrapper import AssumptionsWrapper, is_infinite, is_extended_real
  from sympy.core.symbol import Symbol
  from sympy.core.assumptions import _assume_defined
label_desc: Use image node_id 4 for calling a global function with example usage: test_is_extended_real() without return types