Exports this model to a DOM.

def export_to_dom(self):
        """
        Exports this model to a DOM.
        """
        namespaces = 'xmlns="http://www.neuroml.org/lems/%s" ' + \
                     'xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ' + \
                     'xsi:schemaLocation="http://www.neuroml.org/lems/%s %s"'

        namespaces = namespaces%(self.target_lems_version,self.target_lems_version,self.schema_location)

        xmlstr = '<Lems %s>'%namespaces

        for include in self.includes:
            xmlstr += include.toxml()

        for target in self.targets:
            xmlstr += '<Target component="{0}"/>'.format(target)

        for dimension in self.dimensions:
            xmlstr += dimension.toxml()
            
        for unit in self.units:
            xmlstr += unit.toxml()
            
        for constant in self.constants:
            xmlstr += constant.toxml()
            
        for component_type in self.component_types:
            xmlstr += component_type.toxml()
            
        for component in self.components:
            xmlstr += component.toxml()
            
        xmlstr += '</Lems>'

        xmldom = minidom.parseString(xmlstr)
        return xmldom