>>> from metriques import cost_despl, dist_manh, dist_txeb

>>> cost_despl(1,2,3,4,dist_manh,1.5)
6.0
>>> cost_despl(1,2,3,4,dist_txeb,1.5)
3.0
>>> cost_despl(-3,-4,-1,-2,dist_manh,1.5)
6.0
>>> cost_despl(1,-9,9,4,dist_manh,1.5)
31.5
>>> cost_despl(-4,-4,1,-2,dist_txeb,2.5)
12.5
>>> cost_despl(4,9,7,-1,dist_txeb,2.5)
25.0
>>> cost_despl(5,-3,5,-3,dist_manh,2.5)
0.0