legislation_cosponsors: 115-sres-256, H001041

Cosponsors for tracked legislation. Distinguishes original cosponsors (signed on at introduction) from later additions. Linked to congress_members via bioguide_id.

This data as json

bill_id	bioguide_id	full_name	party	state	sponsorship_date	is_original_cosponsor
115-sres-256	H001041	Sen. Heller, Dean [R-NV]	R	NV	2017-09-14	1