docs: def calculate_priority(ratios=None, **kwargs):
      "Calculates a priority score based on a number of attributes."
      if not ratios:
          ratios = PRIORITY_FEATURE_WEIGHTS
      scores = [DEFAULT_PRIORITY_SCORE]
      for key, value in kwargs.items():
          if key not in PRIORITY_FEATURE_WEIGHTS:
              raise KeyError('The following keyword arguments are supported: '
                             '{keys}'.format(keys=PRIORITY_FEATURES))
          if value is True:
              scores.append(PRIORITY_FEATURE_WEIGHTS[key])
      return float(sum(scores)) / len(scores)