How to use the synapseclient.utils.is_synapse_id function in synapseclient

def cleanup(items):
    """cleanup junk created during testing"""
    for item in reversed(items):
        if isinstance(item, Entity) or utils.is_synapse_id(item) or hasattr(item, 'deleteURI'):
            try:
                syn.delete(item)
            except Exception as ex:
                if hasattr(ex, 'response') and ex.response.status_code in [404, 403]:
                    pass
                else:
                    print("Error cleaning up entity: " + str(ex))
        elif isinstance(item, six.string_types):
            if os.path.exists(item):
                try:
                    if os.path.isdir(item):
                        shutil.rmtree(item)
                    else:  # Assume that remove will work on anything besides folders
                        os.remove(item)
                except Exception as ex:
                    print(ex)

def printEntity(self, entity):
        """Pretty prints an Entity."""
        
        if utils.is_synapse_id(entity):
            entity = self._getEntity(entity)
        try:
            print json.dumps(entity, sort_keys=True, indent=2)
        except TypeError:
            print str(entity)

def _getBenefactor(self, entity):
        """An Entity gets its ACL from its benefactor."""

        if utils.is_synapse_id(entity) or synapseclient.entity.is_synapse_entity(entity):
            return self.restGET('/entity/%s/benefactor' % id_of(entity))
        return entity

:param x: a list of column headers, a Schema, a TableSchema's Synapse ID, or a string prefix
        :Return: a generator of Column objects
        """
        if x is None:
            uri = '/column'
            for result in self._GET_paginated(uri, limit=limit, offset=offset):
                yield Column(**result)
        elif isinstance(x, (list, tuple)):
            for header in x:
                try:
                    int(header)
                    yield self.getColumn(header)
                except ValueError:
                    pass
        elif isinstance(x, Schema) or utils.is_synapse_id(x):
            uri = '/entity/{id}/column'.format(id=id_of(x))
            for result in self._GET_paginated(uri, limit=limit, offset=offset):
                yield Column(**result)
        elif isinstance(x, basestring):
            uri = '/column?prefix=' + x
            for result in self._GET_paginated(uri, limit=limit, offset=offset):
                yield Column(**result)
        else:
            ValueError("Can't get columns for a %s" % type(x))

- :py:func:`synapseutils.sync.syncToSynapse`

    Example:
    Download and print the paths of all downloaded files::

        entities = syncFromSynapse(syn, "syn1234")
        for f in entities:
            print(f.path)

    """
    # initialize the result list
    if allFiles is None:
        allFiles = list()

    # perform validation check on user input
    if is_synapse_id(entity):
        entity = syn.get(entity, downloadLocation=path, ifcollision=ifcollision, followLink=followLink)

    if isinstance(entity, File):
        allFiles.append(entity)
        return allFiles

    entity_id = id_of(entity)
    if not is_container(entity):
        raise ValueError("The provided id: %s is neither a container nor a File" % entity_id)

    # get the immediate children as iterator
    children = syn.getChildren(entity_id)

    # process each child
    for child in children:
        if is_container(child):