def METHOD_NAME(v):
    """Check if v is an array of size(3), [x,y,z], or pg.Pos.
    Examples
    --------
    >>> import pygimli as pg
    >>> print(pg.isPos([0.0, 0.0, 1.]))
    True
    >>> print(pg.isPos(pg.Pos(0.0, 0.0, 0.0)))
    True
    >>> print(pg.isPos(np.ones(3)))
    True
    >>> print(pg.isPos(np.ones(4)))
    False
    """
    return isArray(v, 2) or isArray(v, 3) or isinstance(v, RVector3)