class RubyXL::OOXMLTopLevelObject

def self.set_namespaces(namespace_hash)

'xmlns:r' => 'http://schemas.openxmlformats.org/officeDocument/2006/relationships')
set_namespaces('xmlns' => 'http://schemas.openxmlformats.org/spreadsheetml/2006/main',
==== Examples
* +namespace_hash+ - Hash of namespaces in the form of "prefix" => "url"
=== Parameters
Sets the list of namespaces on this object to be added when writing out XML. Valid only on top-level objects. 
def self.set_namespaces(namespace_hash)
  self.class_variable_set(:@@ooxml_namespaces, namespace_hash)
end