Macro _self no longer possible in Craft 3 This used to work in Craft 2:

{% macro richText(macroParam) %}
  {{ macroParam |striptags('&lt;br&gt;&lt;p&gt;&lt;li&gt;&lt;ul&gt;&lt;a&gt;&lt;strong&gt;&lt;i&gt;')|raw }}
{% endmacro %}

{# include the richtext macro on multiple occasion into another macro #}    
{% macro memberMolecule( entryParam ) %}
  {{ _self.richText(entryParam.body) }}
{% endmacro %}


Now in Craft 3 this causes the error: 


  Impossible to invoke a method ("richText") on a string variable
  ("path/to/file/with/the/macro").


How do I have to rewrite this for Craft 3?
You have to import the macro 

{# include the richtext macro on multiple occasion into another macro #}    
{% macro memberMolecule( entryParam ) %}
    {% import _self as macro %}
    {{ macro.richText(entryParam.body) }}
{% endmacro %}