The load data function

def load_data(filename):
    f = open(filename, 'r'); lines = f.readlines(); f.close()
    dt = float(lines[1])
    ynames = lines[2].split()
    y = {}
    for name in ynames:  # make y a dictionary of (empty) lists
        y[name] = []

    for line in lines[3:]:
        yvalues = [float(yi) for yi in line.split()]
        if len(yvalues) == 0: continue  # skip blank lines
        for name, value in zip(ynames, yvalues):
            y[name].append(value)
    return y, dt