def _verify_forward_declarations_used(self, forward_declarations,<EOL>decl_uses, file_uses):
for cls in forward_declarations:<EOL><INDENT>if cls in file_uses:<EOL><INDENT>if not decl_uses[cls] & USES_DECLARATION:<EOL><INDENT>node = forward_declarations[cls]<EOL>msg = ("<STR_LIT>"<EOL>'<STR_LIT>'.format(cls))<EOL>self._add_warning(msg, node)<EOL><DEDENT><DEDENT>else:<EOL><INDENT>if decl_uses[cls] == UNUSED:<EOL><INDENT>node = forward_declarations[cls]<EOL>msg = "<STR_LIT>".format(cls)<EOL>self._add_warning(msg, node)<EOL><DEDENT><DEDENT><DEDENT>
Find all the forward declarations that are not used.