code: def get_rect_ymin(data):
      """Find minimum y value from four (x,y) vertices."""
      return min(data[0][1], data[1][1], data[2][1], data[3][1])
  
imports: import math
  import warnings
  import matplotlib.dates
  from matplotlib import __version__
label_desc: Use image node_id 23 for calling a global function with example usage: get_rect_ymin(data) and returns: min