<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def legal_form(self):
 """In some cases, the legal form is stored in the JSON-data. In other cases, an ELF-code, consisting of mix of exactly four letters and numbers are stored. This ELF-code can be looked up in a registry where a code maps to a organizational type. ELF-codes are not unique, it can reoccur under different names in different countries"""


        if ATTR_ENTITY_LEGAL_FORM in self.raw:
            try:
                return LEGAL_FORMS[self.legal_jurisdiction][
                    self.raw[ATTR_ENTITY_LEGAL_FORM][
                        ATTR_ENTITY_LEGAL_FORM_CODE][ATTR_DOLLAR_SIGN]
                ]
            except KeyError:
                legal_form = self.raw[
                    ATTR_ENTITY_LEGAL_FORM][
                    ATTR_ENTITY_LEGAL_FORM_CODE][ATTR_DOLLAR_SIGN]

                if len(legal_form) == 4:
                    # If this is returned, the ELF should
                    # be added to the constants.
                    return 'ELF code: ' + legal_form
                else:
                    return legal_form