def parse_kwargs(**kwargs):
    """
        Parses key-word arguments.
        It checks for the presence of key-words ending with '_col', these are
        popped and stored in a seperate dictionary, as they are to be passed
        to the constructor of the actual column or combobox (attribute mappings)
        In addition it sets a number of default attributes for the CellRenderer.
        
        Returns a tuple containing a dict with the CellRenderer attributes and a
        dict with the TreeViewColumn attribute mappings
    """
    kwargs['xalign'] = kwargs.get('xalign', 0.5)
    kwargs['yalign'] = kwargs.get('yalign', 0.5)
    col_attrs = dict()
    for key, value in dict(kwargs).items():
        if key.endswith('_col'):
            col_attrs[key[:-4]] = value
            kwargs.pop(key)
    return kwargs, col_attrs
