|The xsl:import element is only allowed as a top-level element. The xsl:import element children must precede all other element
children of an xsl:stylesheet element, including any xsl:include element children. When xsl:include is used to include a stylesheet,
any xsl:import elements in the included document are moved up in the including document to after any existing xsl:import elements
in the including document. It is an error if a stylesheet directly or indirectly imports itself.
Examples (xslt:xml): Overview