docs: def nearest_interval(self, interval):
          """
          This function returns the nearest interval to any given interval.
          """
          thresh_range = 25  # in cents
          if interval < self.intervals[0] - thresh_range or interval > self.intervals[-1] + thresh_range:
              raise IndexError("The interval given is beyond " + str(thresh_range)
                               + " cents over the range of intervals defined.")
  
          index = find_nearest_index(self.intervals, interval)
          return self.intervals[index]