code: def test_pivot():
      for _ in range(10):
          m = randMatrix(5)
          rref = m.rref()
          for _ in range(5):
              i, j = randint(0, 4), randint(0, 4)
              if m[i, j] != 0:
                  assert LRASolver._pivot(m, i, j).rref() == rref
  
imports: from sympy.core.numbers import Rational, I, oo
  from sympy.core.relational import Eq
  from sympy.core.symbol import symbols
  from sympy.core.singleton import S
  from sympy.matrices.dense import Matrix
  from sympy.matrices.dense import randMatrix
  from sympy.assumptions.ask import Q
  from sympy.logic.boolalg import And
  from sympy.abc import x, y, z
  from sympy.assumptions.cnf import CNF, EncodedCNF
  from sympy.functions.elementary.trigonometric import cos
  from sympy.external import import_module
  from sympy.logic.algorithms.lra_theory import LRASolver, UnhandledInput, LRARational, HANDLE_NEGATION
  from sympy.core.random import random, choice, randint
  from sympy.core.sympify import sympify
  from sympy.ntheory.generate import randprime
  from sympy.core.relational import StrictLessThan, StrictGreaterThan
  import itertools
  from sympy.testing.pytest import raises, XFAIL, skip
label_desc: Use image node_id 14 for calling a global function with example usage: test_pivot() without return types