import csv


def read_file(filename):
    """Read csv file with rows: x, y"""
    px = []
    py = []
    with open(filename) as csv_file:
        csv_reader = csv.reader(csv_file, delimiter=',')

        for row in csv_reader:
            px.append(float(row[0]))
            py.append(float(row[1]))

    return px, py