Python convert sentence stored vertically (column wise) to row

Hi, I have a file where sentence text is stored vertically (column wise) i.e. one sentence span into number of rows(one word stored in each row). Each sentence is separated by tag.I am trying to convert this format into row-wise i.e. each sentence should store into one row.Attached is code snippet I wrote , however I am not getting any value in new dataframe. Any idea whats wrong I am doing ? There must be some clever way of writing python code as I am very new to python programming.