docs: def error_unzip_helper(values, func, func_kwargs):
      '''Splits [(x1, y1), (x2, y2), ...] and gives to func'''
      x_values = [x for x, y in values]
      y_values = [y for x, y in values]
      result = func(x_values, y_values, **func_kwargs)
      if isinstance(result, float):
          return result
      else:
          return result[0]