code: def test_zero_positive():
      assert (
          satask(Q.zero(x + y), Q.positive(x) & Q.positive(y)) is False
      )
      assert (
          satask(Q.positive(x) & Q.positive(y), Q.zero(x + y)) is False
      )
      assert (
          satask(Q.nonzero(x + y), Q.positive(x) & Q.positive(y))
          is True
      )
      assert (
          satask(Q.positive(x) & Q.positive(y), Q.nonzero(x + y))
          is None
      )
  
      # This one requires several levels of forward chaining
      assert (
          satask(Q.zero(x * (x + y)), Q.positive(x) & Q.positive(y))
          is False
      )
  
      assert (
          satask(
              Q.positive(pi * x * y + 1), Q.positive(x) & Q.positive(y)
          )
          is True
      )
      assert (
          satask(
              Q.positive(pi * x * y - 5), Q.positive(x) & Q.positive(y)
          )
          is None
      )
  
imports: from sympy.assumptions.ask import Q
  from sympy.assumptions.assume import assuming
  from sympy.core.numbers import I, pi
  from sympy.core.relational import Eq, Gt
  from sympy.core.singleton import S
  from sympy.core.symbol import symbols
  from sympy.functions.elementary.complexes import Abs
  from sympy.logic.boolalg import Implies
  from sympy.matrices.expressions.matexpr import MatrixSymbol
  from sympy.assumptions.cnf import CNF, Literal
  from sympy.assumptions.satask import satask, extract_predargs, get_relevant_clsfacts
  from sympy.testing.pytest import raises, XFAIL
label_desc: Use image node_id 3 for calling a global function with example usage: test_zero_positive() without return types