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who wrote season 7 of game of thrones
Game of Thrones used seven writers in six seasons. Series creators David Benioff and D. B. Weiss, the showrunners, write most of the episodes each season.
is the storyline of season 7 of game of thrones from the a song of fire and ice series
Season 7 of Game of Thrones largely consisted of original content not found in Martin's A Song of Ice and Fire series.

Question: where did the stroryline come from
Self-contained rewrite: where did the storyline of season 7 of game of thrones come from