Defined in github.com/randym/axlsx/lib/axlsx/package.rb
Initializes your package
Package.new :author => 'you!', :workbook => Workbook.new
A hash that you can use to specify the author and workbook for this
Options Hash (options):
The author of the document
Timestamp in the document properties (defaults to current time).
This is passed to the workbook to specify that shared strings should be
used when serializing the package.
the object that the method was called on
@workbook = nil
@core, @app = Core.new, App.new
@core.creator = options[:author] || @core.creator
@core.created = options[:created_at]
yield self if block_given?