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: meshed_signing_key_accessor.go
    path of file: ./repos/kuma/pkg/core/tokens
    
    the code of the file until where you have to start completion: package tokens

import (
	"context"
	"crypto/rsa"

	"github.com/pkg/errors"

	"github.com/kumahq/kuma/pkg/core/resources/apis/system"
	"github.com/kumahq/kuma/pkg/core/resources/manager"
	"github.com/kumahq/kuma/pkg/core/resources/store"
)

type meshedSigningKeyAccessor struct {
	resManager       manager.ReadOnlyResourceManager
	signingKeyPrefix string
	mesh             string
}

var _ SigningKeyAccessor = &
    
func (s *meshedSigningKeyAccessor) getKeyBytes(ctx context.Context, keyID KeyID) ([]byte, error) {
	resource := system.NewSecretResource()
	if err := s.resManager.Get(ctx, resource, store.GetBy(SigningKeyResourceKey(s.signingKeyPrefix, keyID, s.mesh))); err != nil {
		if store.IsResourceNotFound(err) {
			return nil, &SigningKeyNotFound{
				KeyID:  keyID,
				Prefix: s.signingKeyPrefix,
				Mesh:   s.mesh,
			}
		}
		return nil, errors.Wrap(err, "could not retrieve signing key")
	}
	return resource.Spec.GetData().GetValue(), nil
}