Get the result of _get_target, cache it and return it.

        Args:
            target (str): target to find.

        Returns:
            Package/Module: package containing target or corresponding module.

def get_target(self, target):
        """
        Get the result of _get_target, cache it and return it.

        Args:
            target (str): target to find.

        Returns:
            Package/Module: package containing target or corresponding module.
        """
        if target not in self._target_cache:
            self._target_cache[target] = self._get_target(target)
        return self._target_cache[target]