def pre_modify(self):
        info("\nPre-verifying Debian dependency keys...")
        # Run rosdep update is needed
        if not self.has_run_rosdep:
            self.update_rosdep()

        peer_packages = [p.name for p in self.packages.values()]

        while not self._check_all_keys_are_valid(peer_packages):
            error("Some of the dependencies for packages in this repository could not be resolved by rosdep.")
            error("You can try to address the issues which appear above and try again if you wish.")
            try:
                if not maybe_continue(msg="Would you like to try again?"):
                    error("User aborted after rosdep keys were not resolved.")
                    sys.exit(code.GENERATOR_NO_ROSDEP_KEY_FOR_DISTRO)
            except (__HOLE__, EOFError):
                error("\nUser quit.", exit=True)
            update_rosdep()
            invalidate_view_cache()

        info("All keys are " + ansi('greenf') + "OK" + ansi('reset') + "\n")
dataset/ETHPy150Open ros-infrastructure/bloom/bloom/generators/debian/generator.py/DebianGenerator.pre_modify