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LISBON, PORTUGAL - OCTOBER 18: Borussia DortmundÕs forward Pierre-Emerick Aubameyang during the UEFA Champions League match between Sporting Clube de Portugal and Borussia Dortmund at Estadio Jose Alvalade on October 18, 2016 in Lisbon, Portugal. (Photo by Gualter Fatia/Getty Images)

LISBON, PORTUGAL - OCTOBER 18: Borussia DortmundÕs forward Pierre-Emerick Aubameyang during the UEFA Champions League match between Sporting Clube de Portugal and Borussia Dortmund at Estadio Jose Alvalade on October 18, 2016 in Lisbon, Portugal.  (Photo by Gualter Fatia/Getty Images)

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Dortmund's Gabonese striker Pierre-Emerick Aubameyang celebrates after his goal during the German Cup DFB Pokal third round match between Borussia Dortmund and FC Augsburg in Augsburg on December 16, 2015. / AFP / Christof STACHE / RESTRICTIONS: ACCORDING TO DFB RULES IMAGE SEQUENCES TO SIMULATE VIDEO IS NOT ALLOWED DURING MATCH TIME. MOBILE (MMS) USE IS NOT ALLOWED DURING AND FOR FURTHER TWO HOURS AFTER THE MATCH. == RESTRICTED TO EDITORIAL USE == FOR MORE INFORMATION CONTACT DFB DIRECTLY AT +49 69 67880 / (Photo credit should read CHRISTOF STACHE/AFP/Getty Images)

Dortmund's Gabonese striker Pierre-Emerick Aubameyang celebrates after his goal during the German Cup DFB Pokal third round match between Borussia Dortmund and FC Augsburg in Augsburg on December 16, 2015.  / AFP / Christof STACHE / RESTRICTIONS: ACCORDING TO DFB RULES IMAGE SEQUENCES TO SIMULATE VIDEO IS NOT ALLOWED DURING MATCH TIME. MOBILE (MMS) USE IS NOT ALLOWED DURING AND FOR FURTHER TWO HOURS AFTER THE MATCH. == RESTRICTED TO EDITORIAL USE == FOR MORE INFORMATION CONTACT DFB DIRECTLY AT +49 69 67880

 /         (Photo credit should read CHRISTOF STACHE/AFP/Getty Images)

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DORTMUND, GERMANY - SEPTEMBER 20: Pierre-Emerick Aubameyang of Dortmund celebrates his team's third goal during the Bundesliga match between Borussia Dortmund and Bayer Leverkusen at Signal Iduna Park on September 20, 2015 in Dortmund, Germany. (Photo by Alex Grimm/Bongarts/Getty Images)

DORTMUND, GERMANY - SEPTEMBER 20: Pierre-Emerick Aubameyang of Dortmund celebrates his team's third goal during the Bundesliga match between Borussia Dortmund and Bayer Leverkusen at Signal Iduna Park on September 20, 2015 in Dortmund, Germany.  (Photo by Alex Grimm/Bongarts/Getty Images)

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DORTMUND, GERMANY - APRIL 02: Pierre-Emerick Aubameyang of Borussia Dortmund celebrates scoring his team's first goal during the Bundesliga match between Borussia Dortmund and Werder Bremen at Signal Iduna Park on April 2, 2016 in Dortmund, Germany. (Photo by Dean Mouhtaropoulos/Bongarts/Getty Images)

DORTMUND, GERMANY - APRIL 02:  Pierre-Emerick Aubameyang of Borussia Dortmund celebrates scoring his team's first goal during the Bundesliga match between Borussia Dortmund and Werder Bremen at Signal Iduna Park on April 2, 2016 in Dortmund, Germany.  (Photo by Dean Mouhtaropoulos/Bongarts/Getty Images)

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PORTO, PORTUGAL - FEBRUARY 25: Pierre-Emerick Aubameyang of Dortmund during the UEFA Europa League Round of 32 second leg match against FC Porto at Estadio do Dragao on February 25, 2016 in Porto, Portugal. (Photo by Octavio Passos/Bongarts/Getty Images)

PORTO, PORTUGAL - FEBRUARY 25: Pierre-Emerick Aubameyang of Dortmund during the UEFA Europa League Round of 32 second leg match against FC Porto at Estadio do Dragao on February 25, 2016 in Porto, Portugal.  (Photo by Octavio Passos/Bongarts/Getty Images)