Histogram function

def _Histogram(data, start_range, end_range, delta, x1, x2, y1, y2):

    # the histogram of the data
    bins = []
    while (start_range < end_range):
        bins.append(start_range)
        start_range = start_range + delta

    values, bins, patches = plt.hist(data, bins, normed=False)

    plt.xlabel('Input Data Value')
    plt.ylabel('Occurrence')
    plt.grid(True)
    plt.axis([x1, x2, y1, y2])
    plt.show()

def _Histogram(data, min_val, max_val, delta):

    mid_val = 0.5*(min_val + max_val)
    if (abs(max_val - mid_val) > abs(min_val - mid_val)):
        start_range = mid_val - abs(max_val - mid_val)
        end_range = mid_val + abs(max_val - mid_val)
    else:
        start_range = mid_val - abs(min_val - mid_val)
        end_range = mid_val + abs(min_val - mid_val)

    # the histogram of the data
    bins = []
    start_range_tmp = start_range
    while (start_range_tmp < end_range):
        bins.append(start_range_tmp)
        start_range_tmp = start_range_tmp + delta

    values, bins, patches = plt.hist(data, bins, normed=False)

    plt.xlabel('Input Data Value')
    plt.ylabel('Occurrence')
    plt.grid(True)
    plt.axis([start_range, end_range, 0, np.max(values)])
    plt.show()

    return 0