def unitNormEqual(parts):
    """
    Given a certain number of parts, return a list unit-interval values
    between 0 and 1, with as many divisions as parts; 0 and 1 are always inclusive.

    >>> sieve.unitNormEqual(3)
    [0.0, 0.5, 1]

    If parts is 0 or 1, then a single entry of [0] is given:

    >>> sieve.unitNormEqual(1)
    [0]
    """
    if parts <= 1:
        return [0]
    elif parts == 2:
        return [0, 1]
    else:
        unit = []
        step = 1 / (parts - 1)
        for y in range(parts - 1):
            unit.append(y * step)
        unit.append(1)
        return unit
