Pipfile.lock divided by PyPI and external dependencies.

def _lockfile(self):
        """Pipfile.lock divided by PyPI and external dependencies."""
        pfile = pipfile.load(self.pipfile_location, inject_env=False)
        lockfile = json.loads(pfile.lock())
        for section in ("default", "develop"):
            lock_section = lockfile.get(section, {})
            for key in list(lock_section.keys()):
                norm_key = pep423_name(key)
                lockfile[section][norm_key] = lock_section.pop(key)
        return lockfile