class_docstr: A little class to represent an interior node in the tree
  
  This is analogous to SymPy.Basic for non-Atoms
code: def __hash__(self):
      return hash((type(self), self.op, self.args))
  
imports: from sympy.utilities.iterables import kbins
label_desc: Use image node_id 3 for calling the Compound obj's underlying member method code with example usage: obj.__hash__() and returns: hash