q_text = coll.find({'$text':{'$search':'Duck','$caseSensitive':True}})
q_text.count()
create text index
coll.create_index([("$**","text")])
q_text = coll.find({'$text':{'$search':'doubt'}})
q_text.count()
q_text = coll.find({'$text':{'$search':'ke'}},{'score':{'$meta':'textScore'}})
q_text.sort([('score',{'$meta':'textScore'})])