class_docstr: Tool to maintain statistical data in a window.
      
code: def min(self):
      if self.count > 0:
          return np.min(self.items[: self.count])
      else:
          return None
  
imports: import numpy
label_desc: Use image node_id 4 for calling the WindowStat obj's underlying member method code with example usage: obj.min() and returns: np, None