 True when Property is a property of the current header. 
Defined properties are:
True when Property is a property of the current header. 
Defined properties are:
- filetype(-Type)
- Type is one of file,link,socket,character_device,block_device,directoryorfifo. 
It appears that this library can also return other values. These are 
returned as an integer.
- mtime(-Time)
- True when entry was last modified at time.
- size(-Bytes)
- True when entry is Bytes long.
- link_target(-Target)
- Target for a link. Currently only supported for symbolic 
links.
- format(-Format)
- Provides the name of the archive format applicable to the current entry. 
The returned value is the lowercase version of the output of archive_format_name().
- permissions(-Integer)
- True when entry has the indicated permission mask.