Pytsk3: Reading FS Block Flags via Python

Is there any possibility to read filesystem block flags under python? I cannot find any exposed functions for this. I found this (Add support for unallocated space within volume. · Issue #19 · py4n6/pytsk · GitHub) issue that describes the problem with callback functions, so is there any workaround to get a TSK_FS_BLOCK structure or another way to get unallocated fs blocks via python (os independent)?