signature/policy_config.go
func NewPRSignedByKeyPath(keyType sbKeyType, keyPath string, signedIdentity PolicyReferenceMatch) (PolicyRequirement, error) {
	return newPRSignedByKeyPath(keyType, keyPath, signedIdentity)
}
func NewPRSignedByKeyPath(keyType sbKeyType, keyPath string, signedIdentity PolicyReferenceMatch) (PolicyRequirement, error) {
	return newPRSignedByKeyPath(keyType, keyPath, signedIdentity)
}
// NewPRSignedByKeyPath returns a new "signedBy" PolicyRequirement using a KeyPath