'Check to see if the <xs:import/> already exists
in the specified schema root by matching I{namesapce}.
@param root: A schema root.
@type root: L{Element}'

def exists(self, root):

    for node in root.children:
        if (node.name != 'import'):
            continue
        ns = node.get('namespace')
        if (self.ns == ns):
            return 1
    return 0
