class_docstr: Implement Idle Shell history mechanism.
  
  store - Store source statement (called from pyshell.resetoutput).
  fetch - Fetch stored statement matching prefix already entered.
  history_next - Bound to <<history-next>> event (default Alt-N).
  history_prev - Bound to <<history-prev>> event (default Alt-P).
docstr: Store Shell input statement into history list.
docstr_tok: ["Store","Shell","input","statement","into","history","list","."]
code: def store(self, source):
      "Store Shell input statement into history list."
      source = source.strip()
      if len(source) > 2:
          # avoid duplicates
          try:
              self.history.remove(source)
          except ValueError:
              pass
          self.history.append(source)
      self.pointer = None
      self.prefix = None
  
imports: from idlelib.config import idleConf
label_desc: Use image node_id 5 for calling the History obj's underlying member method code with example usage: obj.store(source) without return types