def relationships
      r = Relationships.new
      r + [tables.relationships,
           worksheet_comments.relationships,
           hyperlinks.relationships,
           worksheet_drawing.relationship,
           pivot_tables.relationships].flatten.compact || []
      r
    end
def relationships
      r = Relationships.new
      r + [tables.relationships,
           worksheet_comments.relationships,
           hyperlinks.relationships,
           worksheet_drawing.relationship,
           pivot_tables.relationships].flatten.compact || []
      r
    end
The worksheet relationships. This is managed automatically by the worksheet
 @return [Relationships]