creates example data set 1

def make_inst1():
    """creates example data set 1"""
    I,d = multidict({1:80, 2:270, 3:250 , 4:160, 5:180}) # demand
    J,M = multidict({1:500, 2:500, 3:500})               # capacity
    c = {(1,1):4,    (1,2):6,    (1,3):9,  # cost
         (2,1):5,    (2,2):4,    (2,3):7,
         (3,1):6,    (3,2):3,    (3,3):4,
         (4,1):8,    (4,2):5,    (4,3):3,
         (5,1):10,   (5,2):8,    (5,3):4,
         }
    return I,J,c,d,M