A municipality is relatively autonomous: it enacts its own "constitution", which is called "organic law" ("Lei Orgânica"), and it is allowed to collect taxes and fees, to maintain a municipal police force (albeit with very restricted powers), to pass laws on any matter that do not contradict either the state or the national constitutions, and to create symbols for itself (like a flag, an anthem and a coat-of-arms). However, not all municipalities exercise all of this autonomy. For instance, only a few municipalities keep local police forces, some of them do not collect some taxes (to attract investors or residents) and many of them do not have a flag (although they are all required to have a coat-of-arms).