public com.google.protobuf.Timestamp getExpireTime() {
    return expireTime_ == null ? com.google.protobuf.Timestamp.getDefaultInstance() : expireTime_;
  }
public com . google . protobuf . Timestamp getExpireTime ( ) { return expireTime_ == null ? com . google . protobuf . Timestamp . getDefaultInstance ( ) : expireTime_ ; }
<pre>
The desired expiration time. If specified, the API will guarantee that
the returned code will not be valid after the specified timestamp;
however, the API cannot guarantee that the returned code will be
valid for at least as long as the requested time (the API puts an upper
bound on the amount of time for which a code may be valid). If omitted,
a default expiration will be used, which may be less than the max
permissible expiration (so specifying an expiration may extend the
code's lifetime over omitting an expiration, even though the API does
impose an upper limit on the maximum expiration that is permitted).
</pre>

<code>.google.protobuf.Timestamp expire_time = 2;</code>