{% macro getParentEntry(thisEntry) %}

    {% import _self as self %}

    {% if thisEntry.parent|length %}

        {% set parent = thisEntry %}

    {% else %}

        {% set parent = false %}

    {% endif %}

{% endmacro %}

{% import _self as self %}
{% set parent = self.getParentEntry( entry ) %}

{% macro hasParentEntry(thisEntry) %}

 {% import _self as self %}

 {% if thisEntry.parent|length %}

   {# would output 1 #}
   {{ true }}

 {% else %}

   {# or just output null #}
   {{ null }}

 {% endif %}

{% endmacro %}

{# This will either be true or null #}
{% set parent = self.hasParentEntry( entry ) %}

{% if parent %}

 {# this will set your parent variable to the entry model or leave the variable as null #}
 {% set parent = entry.parent %}

{% endif %}

{% macro getParentEntry(thisEntry) %}
    {% import _self as self %}
    {% if thisEntry.parent|length %}
        {% set parent = thisEntry %}
    {% else %}
        {% set parent = false %}
    {% endif %}
    {% return parent %}
{% endmacro %}

{% set parent = self.getParentEntry( entry ) %}