For the film, the director Dibakar Banerjee seems to be very keen to take Sushant to Calcutta. Byomkesh Bakshi is a character that is set in the 1930s-40s. Dibakar wants Sushant to soak in the Bengali culture and be comfortable with the ambience. CHECK OUT: Sushant-Parineeti's SHUDDH DESI ROMANCE in Jaipur
Since, this is a film based on a series that is so popular, it is important for the actor to have a sense and feel of the character.
He wants him to get the flavor of the character and Calcutta of those times. Dibakar wants to take him to places and people whose inputs would help the actor get a clue of the backdrop of the film and on the detective Byomkesh Bakshi.