How to use the quilt3.packages.PackageEntry function in quilt3

def _recursive_clean(pkg: quilt3.Package, metadata_reduction_map: Dict[str, bool]):
        # For all keys in current package level
        for key in pkg:
            # If it is a PackageEntry object, we know we have hit a leaf node
            if isinstance(pkg[key], quilt3.packages.PackageEntry):
                # Reduce the metadata to a single value where it can
                cleaned_meta = {}
                for meta_k, meta_v in pkg[key].meta.items():
                    # If the metadata reduction map at the metadata column (or meta_k) can be reduced/ collapsed (True)
                    # Reduce/ collapse the metadata
                    # Reminder: this step will make the metadata access for every file of the same file type the same
                    # format. Example: all files under the key "FOV" will have the same metadata access after this
                    # function runs. All the metadata access for the same file type across the package, if one file has
                    # a list of values for the metadata key, "A", we want all files of the same type to all have list of
                    # values for the metadata key, "A".
                    # We also can't just use a set here for two reasons, the first is simply that sets are not JSON
                    # serializable. "But you can just cast to a set then back to a list!!!". The second reason is that
                    # because a file can have multiple list of values in it's metadata, if we cast to a set, one list
                    # may be reduced to two items while another, different metadata list of values may be reduced to
                    # a single item. Which leads to the problem of matching up metadata to metadata for the same file.
                    # The example to use here is looking at an FOV files metadata: