def defines(self, id, domain='<STR_LIT>'):
assert isinstance(id, (str, unicode))<EOL>assert isinstance(domain, (str, unicode))<EOL>return id in self.messages.get(domain, {})<EOL>
Checks if a message has a translation (it does not take into account
the fallback mechanism).

@rtype: bool
@return: true if the message has a translation, false otherwise