Iterator that returns all the lp objects from linguistic processors layers from the header
        @rtype: L{Clp}
        @return: list of lp objects

def get_lps(self):
        """Iterator that returns all the lp objects from linguistic processors layers from the header
        @rtype: L{Clp}
        @return: list of lp objects
        """
        if self.header is not None:
            for linguisticProcessor in self.header:
                for lp in linguisticProcessor:
                    yield lp