'Read first value of tag with name \'key\'.
>>> from datetime import timedelta
>>> a = RootMetadata()
>>> a.duration = timedelta(seconds=2300)
>>> a.get(\'duration\')
datetime.timedelta(0, 2300)
>>> a.get(\'author\', u\'Anonymous\')
u\'Anonymous\''

def get(self, key, default=None, index=0):

    item = self.getItem(key, index)
    if (item is None):
        if (default is None):
            raise ValueError(("Metadata    has    no    value    '%s'    (index    %s)" % (key, index)))
        else:
            return default
    return item.value
