def get_signature_names(self):
signature_expr = re.compile("<STR_LIT>")<EOL>signatures = []<EOL>for i in self.get_files():<EOL><INDENT>if signature_expr.search(i):<EOL><INDENT>signatures.append(i)<EOL><DEDENT><DEDENT>if len(signatures) > <NUM_LIT:0>:<EOL><INDENT>return signatures<EOL><DEDENT>return None<EOL>
Return a list of the signature file names.