def setUp(self):
        itau_data = get_itau_data_from_file()
        self.header_arquivo = itau_data['header_arquivo']
        self.seg_p = itau_data['seg_p1']
        self.seg_p_str = itau_data['seg_p1_str']
        self.seg_q = itau_data['seg_q1']
        self.seg_q_str = itau_data['seg_q1_str']
def voltage(title, pos, voltage, ax=0):
    """plot voltage vs. position"""
    if ax == 0:
        ax = plt.gca()
    ax.set_title('{} / V'.format(title))
    ax.grid(True)
    ax.plot(pos, voltage)