code: def test_scalar_nan():
      a, e, r = pm.geodetic2aer(nan, nan, nan, *lla0)
      assert isnan(a) and isnan(e) and isnan(r)
  
      lat, lon, alt = pm.aer2geodetic(nan, nan, nan, *lla0)
      assert isnan(lat) and isnan(lon) and isnan(alt)
  
file_path: pymap3d/src/pymap3d/tests/test_geodetic.py
imports: from math import isnan, nan, radians, sqrt
  import pymap3d
  import pytest
  from pytest import approx
label_desc: Use image node_id 12 for calling a global function with example usage: test_scalar_nan() without return types