creates example data set

def make_data(n,m):
    """creates example data set"""
    I = range(1,n+1)
    J = range(1,m+1)
    x,y,w = {},{},{}
    for i in I:
        x[i] = random.randint(0,100)
        y[i] = random.randint(0,100)
        w[i] = random.randint(1,5)
    return I,J,x,y,w