Not everything should be a property in TextAnnotation

[shyamupa]

ta.get_pos and ta.get_ner should be vanilla methods instead of being properties.

For properties, I suggest have ta.pos and ta.ner if we want that functionality.

[nitishgupta]

I also agree with Shyam. I don't see a point of having ta.pos style properties. Just functions should suffice. But, if we do so now, a lot of old code will break. What should we do. I don't know of code apart from Lorelei and My-EL that uses cogcomp-nlpy. So this might be a good time before more people start to use this.