class_docstr: Extends QComboBox to add extra functionality.
  
  * Handles dict mappings -- user selects a text key, and the ComboBox indicates
    the selected value.
  * Requires item strings to be unique
  * Remembers selected value if list is cleared and subsequently repopulated
  * setItems() replaces the items in the ComboBox and blocks signals if the
    value ultimately does not change.
class_docstr_tok: ["Extends","QComboBox","to","add","extra","functionality",".","*","Handles","dict","mappings","--","user","selects","a","text","key",",","and","the","ComboBox","indicates","the","selected","value",".","*","Requires","item","strings","to","be","unique","*","Remembers","selected","value","if","list","is","cleared","and","subsequently","repopulated","*","setItems","(",")","replaces","the","items","in","the","ComboBox","and","blocks","signals","if","the","value","ultimately","does","not","change","."]
docstr: If items were given as a list of strings, then return the currently 
  selected text. If items were given as a dict, then return the value
  corresponding to the currently selected key. If the combo list is empty,
  return None.
docstr_tok: ["If","items","were","given","as","a","list","of","strings",",","then","return","the","currently","selected","text",".","If","items","were","given","as","a","dict",",","then","return","the","value","corresponding","to","the","currently","selected","key",".","If","the","combo","list","is","empty",",","return","None","."]
code: def value(self):
      """
      If items were given as a list of strings, then return the currently
      selected text. If items were given as a dict, then return the value
      corresponding to the currently selected key. If the combo list is empty,
      return None.
      """
      if self.count() == 0:
          return None
      text = self.currentText()
      return self._items[text]
  
imports: import sys
  from collections import OrderedDict
  from ..Qt import QtWidgets
label_desc: Use image node_id 4 for calling the ComboBox obj's underlying member method code with example usage: obj.value() and returns: self, None