code: def not_(constraint, **settings):  # XXX: not a decorator, should be?
      """invert the region where the given constraints are valid, then solve
  
      Inputs:
          constraint -- constraint function
  
      Additional Inputs:
          maxiter -- maximum number of iterations to attempt to solve [default: 100]
          onexit -- function x' = f(x) to call on success [default: None]
          onfail -- function x' = f(x) to call on failure [default: None]
  
      NOTE:
          If a repeating cycle is detected, some of the inputs may be randomized.
      """
      import random as rnd
  
      if "maxiter" in settings:
          maxiter = settings["maxiter"]
          del settings["maxiter"]
      else:
          maxiter = 100
      if "onexit" in settings:
          onexit = settings["onexit"]
          del settings["onexit"]
      else:
          onexit = None
      if "onfail" in settings:
          onfail = settings["onfail"]
          del settings["onfail"]
      else:
          onfail = None
  
      def _constraint(x):
          # check if initial input is valid, else randomize and try again
          for j in range(0, maxiter):
              try:
                  if constraint(x[:]) != x:
                      return x[:] if onexit is None else onexit(x[:])
              except ZeroDivisionError as e:
                  pass  # XXX: do something else?
              except (TypeError, ValueError) as exc:
                  if exc.args[0].find("not supported") and exc.args[
                      0
                  ].rfind("'complex'"):
                      pass  # XXX: do something else?
                  else:
                      raise exc
              x = [(i + rnd.randint(-1, 1)) * rnd.random() for i in x]
          # give up #XXX: or fail with Error?
          return x[:] if onfail is None else onfail(x[:])
  
      cf = lambda x: _constraint(x)
      cfdoc = (
          "NOT( " + constraint.__doc__ + " )"
          if constraint.__doc__
          else ""
      )
      cf.__doc__ = cfdoc.rstrip("\n")
      cf.__name__ = "constraint"
      return cf
  
imports: from mystic.math.measures import *
  from mystic.math import almostEqual
  from numpy import sum
  from numpy import asfarray, asarray, choose, zeros, ones, ndarray
  from numpy import shape, broadcast, empty, atleast_1d
  from numpy import round, abs
  from random import randrange, shuffle
  from numpy import array, intersect1d, inf, isnan, where, choose, clip
  from numpy.random import uniform, choice
  from numpy import maximum, minimum
  from numpy import round, abs
  from mystic.tools import synchronized, connected
  from mystic.math.discrete import product_measure
label_desc: Use image node_id 15 for calling a global function with example usage: not_(constraint) and returns: cf, unknown, unknown