code: func GetDHCPMessageType(o dhcp4.Options) DHCPMessageType {
  	v := o.Get(dhcp4.OptionDHCPMessageType)
  	if v == nil {
  		return 0
  	}
  
  	var d DHCPMessageType
  	if err := (&d).UnmarshalBinary(v); err != nil {
  		return 0
  	}
  	return d
  }
docs: // GetDHCPMessageType returns the DHCP message type of `o`.
  //
  // This returns 0 if the option is not present or did not contain a valid
  // value.
  //
  // The DHCP message type option is defined by RFC 2132, Section 9.6.