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: deleter.go
    path of file: ./repos/athens/pkg/storage/gcp
    
    the code of the file until where you have to start completion: package gcp

import (
	"context"

	"github.com/gomods/athens/pkg/errors"
	"github.com/gomods/athens/pkg/observ"
	modupl "github.com/gomods/athens/pkg/storage/module"
)

// Delete implements the (./pkg/storage).Deleter interface and
// removes a version of a module from storage. Returning ErrNotFound
// if the 
    
func (s *Storage) Delete(ctx context.Context, module, version string) error {
	const op errors.Op = "gcp.Delete"
	ctx, span := observ.StartSpan(ctx, op.String())
	defer span.End()
	exists, err := s.Exists(ctx, module, version)
	if err != nil {
		return errors.E(op, err, errors.M(module), errors.V(version))
	}
	if !exists {
		return errors.E(op, errors.M(module), errors.V(version), errors.KindNotFound)
	}
	del := func(ctx context.Context, path string) error {
		return s.bucket.Object(path).Delete(ctx)
	}
	err = modupl.Delete(ctx, module, version, del, s.timeout)
	if err != nil {
		return errors.E(op, err, errors.M(module), errors.V(version))
	}
	return nil
}