'Match by I{targetNamespace} excluding those that
are equal to the specified namespace to prevent
adding an import to itself.
@param root: A schema root.
@type root: L{Element}'

def match(self, root, ns):

    tns = root.get('targetNamespace')
    if len(self.tns):
        matched = (tns in self.tns)
    else:
        matched = 1
    itself = (ns == tns)
    return (matched and (not itself))
