class_docstr: beam with text, optical and textual score
code: def getPrBlank(self):
      return self.optical.prBlank
  
imports: from __future__ import division
  from __future__ import print_function
  import copy
label_desc: Use image node_id 4 for calling the Beam obj's underlying member method code with example usage: obj.getPrBlank() and returns: self