code: func (fs *FlagSet) Uint64(names []string, value uint64, usage string) *uint64 {
  	p := new(uint64)
  	fs.Uint64Var(p, names, value, usage)
  	return p
  }
docs: // Uint64 defines a uint64 flag with specified name, default value, and usage string.
  // The return value is the address of a uint64 variable that stores the value of the flag.