class Xcodeproj::XCScheme::AbstractSchemeAction

def pre_actions=(pre_actions)
  @xml_element.delete_element('PreActions')
  unless pre_actions.empty?
    pre_actions_element = @xml_element.add_element('PreActions')
    pre_actions.each do |entry_node|
      pre_actions_element.add_element(entry_node.xml_element)
    end
  end
  pre_actions
end