code: def test_pos_neg():
      assert satask(~Q.positive(x), Q.negative(x)) is True
      assert satask(~Q.negative(x), Q.positive(x)) is True
      assert (
          satask(Q.positive(x + y), Q.positive(x) & Q.positive(y))
          is True
      )
      assert (
          satask(Q.negative(x + y), Q.negative(x) & Q.negative(y))
          is True
      )
      assert (
          satask(Q.positive(x + y), Q.negative(x) & Q.negative(y))
          is False
      )
      assert (
          satask(Q.negative(x + y), Q.positive(x) & Q.positive(y))
          is False
      )
  
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 15 for calling a global function with example usage: test_pos_neg() without return types