code: def calc_contours(data, num_contours):
      
      mn = np.nanmean(data)
      top = np.nanmax(data)
      levels = np.linspace(mn, top, num_contours)
      return get_contours(data, levels)
docs: Get sets of contour points for numpy array `data`.
      `num_contours` specifies the number (int) of contours to make.
      Returns a list of numpy arrays of points--each array makes a polygon
      if plotted as such.