def orthologize(self, species_id: str) -> "BEL":
        """Orthologize BEL AST to given species_id

        Will return original entity (ns:value) if no ortholog found.

        Args:
            species_id (str): species id to convert genes/rna/proteins into

        Returns:
            BEL: returns self
        """

        if not self.ast:
            return self

        # Collect canonical/decanonical NSArg values
        if not self.ast.collected_orthologs:
            self = self.collect_orthologs([species_id])

        self.ast.species = set()
        self.ast = bel_utils.orthologize(self.ast, self, species_id)

        return self