adding_string_format_explanation

docs/design_guide.rst

@@ -653,6 +653,14 @@ You could other examples if needed featuring different
 functionalities of the library.
 If you add additional examples, be sure to include them in the ``examples.rst``. Naming of the examples
 files should use the name of the library followed by a description, using underscore to separate them.
+When using print statements you should use the ``" ".format()`` format, as there are particular boards
+that are not capable to use f-strings.
+
+.. code-block:: python
+
+  text_to_display = "World!"
+
+  print("Hello {}".format(text_to_display))
 
 Sensor properties and units
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