You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: watchdog.go
    path of file: ./repos/kubeedge/vendor/github.com/coreos/go-systemd/v22/daemon
    
    the code of the file until where you have to start completion: // Copyright 2016 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT
    
func SdWatchdogEnabled(unsetEnvironment bool) (time.Duration, error) {
	wusec := os.Getenv("WATCHDOG_USEC")
	wpid := os.Getenv("WATCHDOG_PID")
	if unsetEnvironment {
		wusecErr := os.Unsetenv("WATCHDOG_USEC")
		wpidErr := os.Unsetenv("WATCHDOG_PID")
		if wusecErr != nil {
			return 0, wusecErr
		}
		if wpidErr != nil {
			return 0, wpidErr
		}
	}

	if wusec == "" {
		return 0, nil
	}
	s, err := strconv.Atoi(wusec)
	if err != nil {
		return 0, fmt.Errorf("error converting WATCHDOG_USEC: %s", err)
	}
	if s <= 0 {
		return 0, fmt.Errorf("error WATCHDOG_USEC must be a positive number")
	}
	interval := time.Duration(s) * time.Microsecond

	if wpid == "" {
		return interval, nil
	}
	p, err := strconv.Atoi(wpid)
	if err != nil {
		return 0, fmt.Errorf("error converting WATCHDOG_PID: %s", err)
	}
	if os.Getpid() != p {
		return 0, nil
	}

	return interval, nil
}