This prints, when the key k exists in key2, a empty link, meaning its href is empty. The real value of k in key2 isn't empty.
# data is a dictionary
{% for k, v in data.key1.items %}
  {% if k in data.key2 %}
    <h3><a href='{{data.key2.k}}'>{{k}}</a></h3> <!-- this generates <a href>fdsfdsd</a> -->
  {% else %}
    <h3>{{ k }}</h3>
  {% endif %}
{% endfor %}
How do I fix it?
 
    