def _set_up_down(self, v, load=False):
if hasattr(v, "<STR_LIT>"):<EOL><INDENT>v = v._utype(v)<EOL><DEDENT>try:<EOL><INDENT>t = YANGDynClass(<EOL>v,<EOL>base=YANGBool,<EOL>is_leaf=True,<EOL>yang_name="<STR_LIT>",<EOL>parent=self,<EOL>path_helper=self._path_helper,<EOL>extmethods=self._extmethods,<EOL>register_paths=True,<EOL>namespace="<STR_LIT>",<EOL>defining_module="<STR_LIT>",<EOL>yang_type="<STR_LIT>",<EOL>is_config=False,<EOL>)<EOL><DEDENT>except (TypeError, ValueError):<EOL><INDENT>raise ValueError(<EOL>{<EOL>"<STR_LIT>": """<STR_LIT>""",<EOL>"<STR_LIT>": "<STR_LIT>",<EOL>"<STR_LIT>": """<STR_LIT>""",<EOL>}<EOL>)<EOL><DEDENT>self.__up_down = t<EOL>if hasattr(self, "<STR_LIT>"):<EOL><INDENT>self._set()<EOL><DEDENT>
Setter method for up_down, mapped from YANG variable /network_instances/network_instance/protocols/protocol/isis/levels/level/link_state_database/lsp/tlvs/tlv/ipv6_reachability/prefixes/prefixes/state/up_down (boolean)
    If this variable is read-only (config: false) in the
    source YANG file, then _set_up_down is considered as a private
    method. Backends looking to populate this variable should
    do so via calling thisObj._set_up_down() directly.

    YANG Description: The up/down bit. Set if a prefix is advertised from a higher level to
a lower level (e.g., level 2 to level 1), indicating that the prefix
has traveled down the hierarchy. Prefixes that have the up/down bit
set may only be advertised down the hierarchy, i.e., to lower levels.
When a prefix is first injected into IS-IS, the bit is UNSET.