[Tutor] Unicode Problem

[Rainer Mansfeld]

Hi tutors,

I'm a Python newbie from Germany and in our language we have funny
letters like ä, ö and ü. (That would be ä ö and ü in
HTML.)

Playing around with these, I stumbled upon the following:

    >>> print u'ä', 'ä'
    ä ä
So print can handle Unicode and non-Unicode.

    >>> print u'ä' + 'a'
    äa
Concatenation seems to be no problem either, except in some cases:

    >>> print u'ä' + 'ä'
    Traceback (most recent call last):
      File "<interactive input>", line 1, in ?
    UnicodeDecodeError: 'ascii' codec can't decode byte 0xe4 in
    position 0: ordinal not in range(128)

What's happening here?
Can somebody please explain this to me?
Thanks in advance

    Rainer