public void setChoiceMode(int choiceMode) {
        if (mChoiceMode != choiceMode) {
            mChoiceMode = choiceMode;
            clearSelections();
        }
    }
Defines the choice behavior for the RecyclerView. By default, RecyclerViewChoiceMode does
not have any choice behavior (AbsListView.CHOICE_MODE_NONE). By setting the choiceMode to
AbsListView.CHOICE_MODE_SINGLE, the RecyclerView allows up to one item to  be in a
chosen state.

@param choiceMode One of AbsListView.CHOICE_MODE_NONE, AbsListView.CHOICE_MODE_SINGLE
app/src/main/java/com/example/android/sunshine/app/ItemChoiceManager.java