It shall be unlawful for any person, company, partnership, or corporation, in any manner whatsoever, to prepay the transportation, or in any way assist or encourage the importation or migration of any alien or aliens, any foreigner or foreigners, into the United States, its Territories, or the District of Columbia, under contract or agreement, parol or special, express or implied, made previous to the importation or migration of such alien or aliens, foreigner or foreigners, to perform labor or service of any kind in the United States, its Territories, or the District of Columbia.