code: def solution(self, e, v, extra_constraints=(), exact=None):
          
          if exact is False and o.VALIDATE_APPROXIMATIONS in self.state.options:
              ar = self._solver.solution(e, v, extra_constraints=self._adjust_constraint_list(extra_constraints), exact=False)
              er = self._solver.solution(e, v, extra_constraints=self._adjust_constraint_list(extra_constraints))
              if er is True:
                  assert ar is True
              return ar
          return self._solver.solution(e, v, extra_constraints=self._adjust_constraint_list(extra_constraints), exact=exact)
docs: Return True if `v` is a solution of `expr` with the extra constraints, False otherwise.
  
          :param e:                   An expression (an AST) to evaluate
          :param v:                   The proposed solution (an AST)
          :param extra_constraints:   Extra constraints (as ASTs) to add to the solver for this solve.
          :param exact:               If False, return approximate solutions.
          :return:                    True if `v` is a solution of `expr`, False otherwise