code: private void obtainUnit(@NonNull final TypedArray typedArray) {
          setUnit(typedArray.getText(R.styleable.AbstractUnitPreference_unit));
      }
docs: Obtains the unit, which is used for textual representation of the preference's value, from a
  specific typed array.
  
  @param typedArray
  The typed array, the unit should be obtained from, as an instance of the class {@link
  TypedArray}. The typed array may not be null