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: version.go
    path of file: ./repos/sealos/staging/src/github.com/labring/lvscare/pkg/version
    
    the code of the file until where you have to start completion: /*
Copyright 2016 The Kubernetes Authors.

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 WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package version

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"
)

// Version is an opqaue representation of a version number
type Version struct {
	components    []uint
	semver        bool
	preRelease    string
	buildMetadata string
}

var (
	// versionMatchRE splits a version string into numeric and "extra" parts
	versionMatchRE = regexp.MustCompile(`^\s*v?([0-9]+(?:\.[0-9]+)*)(.*)*$`)
	// extraMatchRE splits the "extra" part of versionMatchRE into semver pre-release and build metadata; it does not validate the "no leading zeroes" constraint for pre-release
	extraMatchRE = regexp.MustCompile(`^(?:-([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?\s*$`)
)

func parse(str str
    
func parse(str string, semver bool) (*Version, error) {
	parts := versionMatchRE.FindStringSubmatch(str)
	if parts == nil {
		return nil, fmt.Errorf("could not parse %q as version", str)
	}
	numbers, extra := parts[1], parts[2]

	components := strings.Split(numbers, ".")
	if (semver && len(components) != 3) || (!semver && len(components) < 2) {
		return nil, fmt.Errorf("illegal version string %q", str)
	}

	v := &Version{
		components: make([]uint, len(components)),
		semver:     semver,
	}
	for i, comp := range components {
		if (i == 0 || semver) && strings.HasPrefix(comp, "0") && comp != "0" {
			return nil, fmt.Errorf("illegal zero-prefixed version component %q in %q", comp, str)
		}
		num, err := strconv.ParseUint(comp, 10, 0)
		if err != nil {
			return nil, fmt.Errorf("illegal non-numeric version component %q in %q: %v", comp, str, err)
		}
		v.components[i] = uint(num)
	}

	if semver && extra != "" {
		extraParts := extraMatchRE.FindStringSubmatch(extra)
		if extraParts == nil {
			return nil, fmt.Errorf("could not parse pre-release/metadata (%s) in version %q", extra, str)
		}
		v.preRelease, v.buildMetadata = extraParts[1], extraParts[2]

		for _, comp := range strings.Split(v.preRelease, ".") {
			if _, err := strconv.ParseUint(comp, 10, 0); err == nil {
				if strings.HasPrefix(comp, "0") && comp != "0" {
					return nil, fmt.Errorf("illegal zero-prefixed version component %q in %q", comp, str)
				}
			}
		}
	}

	return v, nil
}