code: def test__erfs():
      assert _erfs(z).diff(z) == -2 / sqrt(S.Pi) + 2 * z * _erfs(z)
  
      assert _erfs(1 / z).series(z) == z / sqrt(pi) - z**3 / (
          2 * sqrt(pi)
      ) + 3 * z**5 / (4 * sqrt(pi)) + O(z**6)
  
      assert expand(
          erf(z).rewrite("tractable").diff(z).rewrite("intractable")
      ) == erf(z).diff(z)
      assert _erfs(z).rewrite("intractable") == (-erf(z) + 1) * exp(
          z**2
      )
      raises(ArgumentIndexError, lambda: _erfs(z).fdiff(2))
  
imports: from sympy.core.function import diff, expand, expand_func
  from sympy.core import EulerGamma
  from sympy.core.numbers import E, Float, I, Rational, nan, oo, pi
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol, symbols
  from sympy.functions.elementary.complexes import conjugate, im, polar_lift, re
  from sympy.functions.elementary.exponential import exp, exp_polar, log
  from sympy.functions.elementary.hyperbolic import cosh, sinh
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.functions.elementary.trigonometric import cos, sin, sinc
  from sympy.functions.special.error_functions import Chi, Ci, E1, Ei, Li, Shi, Si, erf, erf2, erf2inv, erfc, erfcinv, erfi, erfinv, expint, fresnelc, fresnels, li
  from sympy.functions.special.gamma_functions import gamma, uppergamma
  from sympy.functions.special.hyper import hyper, meijerg
  from sympy.integrals.integrals import Integral, integrate
  from sympy.series.gruntz import gruntz
  from sympy.series.limits import limit
  from sympy.series.order import O
  from sympy.core.expr import unchanged
  from sympy.core.function import ArgumentIndexError
  from sympy.functions.special.error_functions import _erfs, _eis
  from sympy.testing.pytest import raises
label_desc: Use image node_id 4 for calling a global function with example usage: test__erfs() without return types