class_docstr: Generic histogram class for real numbers
  
  Example:
  
      >>> h = Histogram(5)     # Initializing, bin width = 5
      >>> h << [2,3,2,7,8,5,5,0,7,9]     # Adding more items
      >>> print(h)
      N = 10, mean +- sd: 4.8000 +- 2.9740
      [ 0,  5): **** (4)
      [ 5, 10): ****** (6)
docstr: Clears the collected data
docstr_tok: ["Clears","the","collected","data"]
code: def clear(self):
      """Clears the collected data"""
      self._bins = []
      self._min, self._max = None, None
      self._running_mean = RunningMean()
  
imports: import math
label_desc: Use image node_id 9 for calling the Histogram obj's underlying member method code with example usage: obj.clear() without return types