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] 8U2TAXoUNI0: nsig extraction failed: Some formats may be missing
         n = L0F9Ommg23tDfF6Nx ; 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] 8U2TAXoUNI0: nsig extraction failed: Some formats may be missing
         n = 4c7YbUj1O0136kIT1 ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js