how to make template to detect empty richtext fields #600

Hello.
I am trying to do something like this for each entry (e) in my template:

{% for e in entries %}
{{ e.country }}: {{ e.locality }}{%r if e.habitat %}; {{r e.habitat }}{%r endif %}{% if e.substrate %}; {{ e.substrate }}{% endif %}.
{% endfor %}

Basically, I want habitat & substrate fields to be printed preceded by a separator ';' (but ONLY if those fields contain a text; otherwise, the separator and field shouldn't be printed).

from docxtpl import DocxTemplate, RichText as RT
from docx import Document
tpl = DocxTemplate("template.docx")
context = {"entries": [
	{"country":"USA", "locality":"Boston", "habitat":"forest", "substrate":"wood"}, 
	{"country":"USA", "locality":"New Orleans", "habitat":"marsh", "substrate":""}, 
	{"country":"USA", "locality":"Honolulu", "habitat":RT("", color="blue"), "substrate":"water"}, 
	{"country":"USA", "locality":"St. Louis", "habitat":RT("ship", color="blue"), "substrate":"water"}, 
	{"country":"USA", "locality":RT("New York!", color="ff0000"), "habitat":"", "substrate":"concrete"}
]}
tpl.render(context, autoescape=True)
tpl.save("filled-template.docx")

This is a simplified version of my code (I generate my context from a database and I apply RichText using a function depending on some other factors).
But the Honolulu entry illustrates my problem: is there a way my template can detect that RT("", color="blue") is actually an empty text entry, so the {%r if e.habitat %} should not be executed?

Currently, I am getting this text output (I am not showing the bold/italics/coloured output here, since that's not the problem: please notice the double ; separator after Honolulu):

USA: Boston; forest; wood.
USA: New Orleans; marsh.
USA: Honolulu; ; water.
USA: St. Louis; ship; water.
USA: New York!; concrete.