def write_chartsheet # :nodoc:
      schema                 = 'http://schemas.openxmlformats.org/'
      xmlns                  = schema + 'spreadsheetml/2006/main'
      xmlns_r                = schema + 'officeDocument/2006/relationships'
      xmlns_mc               = schema + 'markup-compatibility/2006'
      xmlns_mv               = 'urn:schemas-microsoft-com:mac:vml'
      mc_ignorable           = 'mv'
      mc_preserve_attributes = 'mv:*'

      attributes = [
                    ['xmlns',   xmlns],
                    ['xmlns:r', xmlns_r]
                   ]

      @writer.tag_elements('chartsheet', attributes) do
        yield
      end
    end
def write_chartsheet # :nodoc:
      schema                 = 'http://schemas.openxmlformats.org/'
      xmlns                  = schema + 'spreadsheetml/2006/main'
      xmlns_r                = schema + 'officeDocument/2006/relationships'
      xmlns_mc               = schema + 'markup-compatibility/2006'
      xmlns_mv               = 'urn:schemas-microsoft-com:mac:vml'
      mc_ignorable           = 'mv'
      mc_preserve_attributes = 'mv:*'

      attributes = [
                    ['xmlns',   xmlns],
                    ['xmlns:r', xmlns_r]
                   ]

      @writer.tag_elements('chartsheet', attributes) do
        yield
      end
    end
Write the <chartsheet> element. This is the root element of Chartsheet.