How to use the gitdb.util.bin_to_hex function in gitdb

ldb = LooseObjectDB(os.path.join(rwrepo.git_dir, 'objects'))
		
		for randomize in range(2):
			desc = (randomize and 'random ') or ''
			print >> sys.stderr, "Creating %s data ..." % desc
			st = time()
			size, stream = make_memory_file(self.large_data_size_bytes, randomize)
			elapsed = time() - st
			print >> sys.stderr, "Done (in %f s)" % elapsed
			
			# writing - due to the compression it will seem faster than it is 
			st = time()
			binsha = ldb.store(IStream('blob', size, stream)).binsha
			elapsed_add = time() - st
			assert ldb.has_object(binsha)
			db_file = ldb.readable_db_object_path(bin_to_hex(binsha))
			fsize_kib = os.path.getsize(db_file) / 1000
			
			
			size_kib = size / 1000
			print >> sys.stderr, "Added %i KiB (filesize = %i KiB) of %s data to loose odb in %f s ( %f Write KiB / s)" % (size_kib, fsize_kib, desc, elapsed_add, size_kib / elapsed_add)
			
			# reading all at once
			st = time()
			ostream = ldb.stream(binsha)
			shadata = ostream.read()
			elapsed_readall = time() - st
			
			stream.seek(0)
			assert shadata == stream.getvalue()
			print >> sys.stderr, "Read %i KiB of %s data at once from loose odb in %f s ( %f Read KiB / s)" % (size_kib, desc, elapsed_readall, size_kib / elapsed_readall)

def _map_loose_object(self, sha):
        """
        :return: memory map of that file to allow random read access
        :raise BadObject: if object could not be located"""
        db_path = self.db_path(self.object_path(bin_to_hex(sha)))
        try:
            return file_contents_ro_filepath(db_path, flags=self._fd_open_flags)
        except OSError as e:
            if e.errno != ENOENT:
                # try again without noatime
                try:
                    return file_contents_ro_filepath(db_path)
                except OSError as new_e:
                    raise BadObject(sha) from new_e
                # didn't work because of our flag, don't try it again
                self._fd_open_flags = 0
            else:
                raise BadObject(sha) from e
            # END handle error

:param filepath: full path to the log file
        :param oldbinsha: binary sha of the previous commit
        :param newbinsha: binary sha of the current commit
        :param message: message describing the change to the reference
        :param write: If True, the changes will be written right away. Otherwise
            the change will not be written
        :return: RefLogEntry objects which was appended to the log
        :note: As we are append-only, concurrent access is not a problem as we
            do not interfere with readers."""
        if len(oldbinsha) != 20 or len(newbinsha) != 20:
            raise ValueError("Shas need to be given in binary format")
        # END handle sha type
        assure_directory_exists(filepath, is_file=True)
        committer = isinstance(config_reader, Actor) and config_reader or Actor.committer(config_reader)
        entry = RefLogEntry(
            (bin_to_hex(oldbinsha), bin_to_hex(newbinsha), committer, (int(time.time()), time.altzone), message))

        lf = LockFile(filepath)
        lf._obtain_lock_or_raise()

        fd = open(filepath, 'a')
        try:
            fd.write(repr(entry))
        finally:
            fd.close()
            lf._release_lock()
        # END handle write operation

        return entry

and corresponding index file. The pack contains all OStream objects contained in object iter.
        :param base_dir: directory which is to contain the files
        :return: PackEntity instance initialized with the new pack

        **Note:** for more information on the other parameters see the write_pack method"""
        pack_fd, pack_path = tempfile.mkstemp('', 'pack', base_dir)
        index_fd, index_path = tempfile.mkstemp('', 'index', base_dir)
        pack_write = lambda d: os.write(pack_fd, d)
        index_write = lambda d: os.write(index_fd, d)

        pack_binsha, index_binsha = cls.write_pack(object_iter, pack_write, index_write, object_count, zlib_compression)
        os.close(pack_fd)
        os.close(index_fd)

        fmt = "pack-%s.%s"
        new_pack_path = os.path.join(base_dir, fmt % (bin_to_hex(pack_binsha), 'pack'))
        new_index_path = os.path.join(base_dir, fmt % (bin_to_hex(pack_binsha), 'idx'))
        os.rename(pack_path, new_pack_path)
        os.rename(index_path, new_index_path)

        return cls(new_pack_path)

def hexsha(self):
		""":return: 40 byte hex version of our 20 byte binary sha"""
		return bin_to_hex(self.binsha)

def hexsha(self):
		""":return: 40 byte hex version of our 20 byte binary sha"""
		return bin_to_hex(self.binsha)

def short_to_long(odb, hexsha):
	""":return: long hexadecimal sha1 from the given less-than-40 byte hexsha
		or None if no candidate could be found.
	:param hexsha: hexsha with less than 40 byte"""
	try:
		return bin_to_hex(odb.partial_to_complete_sha_hex(hexsha))
	except BadObject:
		return None
	# END exception handling

:param config_reader: configuration reader of the repository - used to obtain
			user information. May be None
		:param filepath: full path to the log file
		:param oldbinsha: binary sha of the previous commit
		:param newbinsha: binary sha of the current commit
		:param message: message describing the change to the reference
		:param write: If True, the changes will be written right away. Otherwise
			the change will not be written
		:return: RefLogEntry objects which was appended to the log
		:note: As we are append-only, concurrent access is not a problem as we 
			do not interfere with readers."""
		if len(oldbinsha) != 20 or len(newbinsha) != 20:
			raise ValueError("Shas need to be given in binary format")
		#END handle sha type
		assure_directory_exists(filepath, is_file=True)
		entry = RefLogEntry((bin_to_hex(oldbinsha), bin_to_hex(newbinsha), Actor.committer(config_reader), (int(time.time()), time.altzone), message))
		
		lf = LockFile(filepath)
		lf._obtain_lock_or_raise()
		
		fd = open(filepath, 'a')
		try:
			fd.write(repr(entry))
		finally:
			fd.close()
			lf._release_lock()
		#END handle write operation
		
		return entry