fix empty documents - multi_news (#793)

* fix empty documents - multi_news

* fix test - unrecognized variable

Author: VictorSanh

promptsource/templates/multi_news/templates.yaml

@@ -6,6 +6,8 @@ templates:
     jinja: '{% set docs = document.split("3ed2dface8203c4c9dfb1a5dc58e41e0||") | reject("equalto",
       "") | list %}
 
+      {% if document != "" %}
+
       What are the key points across these news articles:
 
       {% for doc in docs %}
@@ -17,7 +19,9 @@ templates:
 
       |||
 
-      {{summary[2:]}}'
+      {{summary[2:]}}
+
+      {% endif %}'
     metadata: !TemplateMetadata
       choices_in_prompt: false
       metrics:
@@ -32,6 +36,8 @@ templates:
     jinja: '{% set docs = document.split("3ed2dface8203c4c9dfb1a5dc58e41e0||") | reject("equalto",
       "") | list %}
 
+      {% if document != "" %}
+
       Synthesize these documents into a single one:
 
       {% for doc in docs %}
@@ -43,7 +49,9 @@ templates:
 
       |||
 
-      {{summary[2:]}}'
+      {{summary[2:]}}
+
+      {% endif %}'
     metadata: !TemplateMetadata
       choices_in_prompt: false
       metrics:
@@ -58,6 +66,8 @@ templates:
     jinja: '{% set docs = document.split("3ed2dface8203c4c9dfb1a5dc58e41e0||") | reject("equalto",
       "") | list %}
 
+      {% if document != "" %}
+
       I want to edit the following articles into a more concise summary:
 
       {% for doc in docs %}
@@ -69,7 +79,9 @@ templates:
 
       |||
 
-      {{summary[2:]}}'
+      {{summary[2:]}}
+
+      {% endif %}'
     metadata: !TemplateMetadata
       choices_in_prompt: false
       metrics:
@@ -84,6 +96,8 @@ templates:
     jinja: '{% set docs = document.split("3ed2dface8203c4c9dfb1a5dc58e41e0||") | reject("equalto",
       "") | list %}
 
+      {% if document != "" %}
+
       Write a summary of the following articles:
 
       {% for doc in docs %}
@@ -95,7 +109,9 @@ templates:
 
       |||
 
-      {{summary[2:]}}'
+      {{summary[2:]}}
+
+      {% endif %}'
     metadata: !TemplateMetadata
       choices_in_prompt: false
       metrics:
@@ -110,13 +126,17 @@ templates:
     jinja: '{% set docs = document.split("3ed2dface8203c4c9dfb1a5dc58e41e0||") | reject("equalto",
       "") | list%}
 
+      {% if document != "" %}
+
       Write an expanded news article with plausible details from the following summary:
 
       {{summary[2:]}}
 
       |||
 
-      {{docs | choice}}'
+      {{docs | choice}}
+
+      {% endif %}'
     metadata: !TemplateMetadata
       choices_in_prompt: false
       metrics:
@@ -131,6 +151,8 @@ templates:
     jinja: '{% set docs = document.split("3ed2dface8203c4c9dfb1a5dc58e41e0||") | reject("equalto",
       "") | list %}
 
+      {% if document != "" %}
+
       I''m trying to distill these articles down into one:
 
       {% for doc in docs %}
@@ -142,7 +164,9 @@ templates:
 
       |||
 
-      {{summary[2:]}}'
+      {{summary[2:]}}
+
+      {% endif %}'
     metadata: !TemplateMetadata
       choices_in_prompt: false
       metrics: