code: def _sin(x):
      '''sine with case for pi multiples'''
      return 0. if np.isclose(np.mod(x, np.pi), 0.) else np.sin(xf _sin(x):
      '''sine with case for pi multiples'''
      return 0. if np.isclose(np.mod(x, np.pi), 0.) else np.sin(x)
docs: sine with case for pi multiples