def __init__(self, select2attrs=None, *args, **kwargs):
self.select2attrs = select2attrs or {}<EOL>assert_msg = "<STR_LIT>"<EOL>assert isinstance(self.select2attrs, dict), assert_msg.format(<EOL>self.select2attrs.__class__.__name__<EOL>)<EOL>if '<STR_LIT:width>' not in self.select2attrs:<EOL><INDENT>self.select2attrs.update({'<STR_LIT:width>': '<STR_LIT>'})<EOL><DEDENT>super(Select2Mixin, self).__init__(*args, **kwargs)<EOL>
Initialize default select2 attributes.

If width is not provided, sets Select2 width to 250px.

Args:
    select2attrs: a dictionary, which then passed to
        Select2 constructor function as options.