diff --git a/squirrelbattle/interfaces.py b/squirrelbattle/interfaces.py
index 50ebb2e..9d13046 100644
--- a/squirrelbattle/interfaces.py
+++ b/squirrelbattle/interfaces.py
@@ -182,6 +182,10 @@ class Map:
             self.add_entity(dictclasses[entisave["type"]](**entisave))
 
     def large_neighbourhood(self, y, x):
+        """
+        Returns up to 8 nearby coordinates, in a 3x3 square around the input coordinate.
+        Does not return coordinates if they are out of bounds.
+        """
         neighbours = []
         for dy, dx in product([-1, 0, 1], [-1, 0, 1]):
             if 0 < y+dy < self.height and 0 < x+dx < self.width: