code: def set_sample_coverage(self, value=1.0, invert=False):
          
          self.glir.command('FUNC', 'glSampleCoverage', float(value), 
                            bool(invert))
docs: Specify multisample coverage parameters
      
          Parameters
          ----------
          value : float
              Sample coverage value (will be clamped between 0. and 1.).
          invert : bool
              Specify if the coverage masks should be inverted.