diff --git a/docs/examples/simulation.md b/docs/examples/simulation.md
index 5ab9580e0..4ae14f246 100644
--- a/docs/examples/simulation.md
+++ b/docs/examples/simulation.md
@@ -250,10 +250,10 @@ experiment.computation += [init, equilibration, bulk, ana]
 New we'd like to upload files associated with our simulation. First, we'll instantiate our File nodes under a specific project.
 
 ```python
-packing_file = cript.File(name="Initial simulation box snapshot with roughly packed molecules", type="computation_snapshot", source="path/to/local/file")
-forcefield_file = cript.File(name="Forcefield definition file", type="data", source="path/to/local/file")
-snap_file = cript.File(name="Bulk measurement initial system snap shot", type="computation_snapshot", source="path/to/local/file")
-final_file = cript.File(name="Final snapshot of the system at the end the simulations", type="computation_snapshot", source="path/to/local/file")
+packing_file = cript.File(name="Initial simulation box snapshot with roughly packed molecules", type="computation_snapshot", source="path/to/local/file", extension=".csv")
+forcefield_file = cript.File(name="Forcefield definition file", type="data", source="path/to/local/file", extension=".pdf")
+snap_file = cript.File(name="Bulk measurement initial system snap shot", type="computation_snapshot", source="path/to/local/file", extension=".png")
+final_file = cript.File(name="Final snapshot of the system at the end the simulations", type="computation_snapshot", source="path/to/local/file", extension=".jpeg")
 ```
 
 !!! note