code: def deselect_option(self, value=None, text=None, index=None):
          
          def do_deselect():
              """
              Perform selection
              """
              return self.set_select('deselect', value, text, index)
          return self.execute_and_handle_webelement_exceptions(do_deselect, 'deselect option')
docs: De-selects an option by value, text, or index. You must name the parameter
  
          @type value:    str
          @param value:   the value of the option
          @type text:     str
          @param text:    the option's visible text
          @type index:    int
          @param index:   the zero-based index of the option
  
          @rtype:     WebElementWrapper
          @return:    self