NewErrInvalidEntity returns an error with the invalids fields and why it is invalid after a validation.

NewErrUnauthorized returns an error with the access is not authorized.

NewErrUnprocessableEntity returns an error when input model has syntax errors.

ErrCodeInvalidEntity is the error code for when he input model is invalid.

ErrCodeUnauthorized is the error code for when the user is not authorized to access the resource.

ErrCodeUnprocessableEntity is the error code for when the input model has syntax errors.

ErrLayer is an error level.