code: def applyaty(self, content, xty):
          
          name = 'type'
          ns = Namespace.xsins
          parent = content.node
          for child in parent.getChildren():
              ref = child.get(name, ns)
              if ref is None:
                  parent.addPrefix(ns[0], ns[1])
                  attr = ':'.join((ns[0], name))
                  child.set(attr, xty)
          return self
docs: Apply the type referenced in the I{arrayType} to the content
          (child nodes) of the array.  Each element (node) in the array
          that does not have an explicit xsi:type attribute is given one
          based on the I{arrayType}.
          @param content: An array content.
          @type content: L{Content}
          @param xty: The XSI type reference.
          @type xty: str
          @return: self
          @rtype: L{Encoded}