Creates iterator to write to new tsv. Contains input tsv
        lines plus quant data for these.

def get_psms(self):
        """Creates iterator to write to new tsv. Contains input tsv
        lines plus quant data for these."""
        self.header = actions.create_header(self.oldheader)
        self.psms = actions.add_genes_to_psm_table(self.fn, self.oldheader,
                                                   self.lookup)