WARNING: [youtube] Falling back to generic n function search
         player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js
WARNING: [youtube] S6F_3ZfkydE: nsig extraction failed: Some formats may be missing
         n = cSH08w17q8rkHKnZ5 ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js
WARNING: [youtube] Falling back to generic n function search
         player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js
WARNING: [youtube] S6F_3ZfkydE: nsig extraction failed: Some formats may be missing
         n = 6-TzCPazK-U3PBPHA ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js