Calculate equal interval breaks.

    Arguments:
    data -- Array of values to classify.
    num_breaks -- Number of breaks to perform.

def equal(data, num_breaks):
    """
    Calculate equal interval breaks.

    Arguments:
    data -- Array of values to classify.
    num_breaks -- Number of breaks to perform.
    """

    step = (numpy.amax(data) - numpy.amin(data)) / num_breaks
    return numpy.linspace(numpy.amin(data) + step, numpy.amax(data), num_breaks)