diff --git a/src/openmc_source_plotter/core.py b/src/openmc_source_plotter/core.py
index 9603f24..40dbb20 100644
--- a/src/openmc_source_plotter/core.py
+++ b/src/openmc_source_plotter/core.py
@@ -9,7 +9,7 @@
 import openmc.lib
 import plotly.graph_objects
 
-import pkg_resources 
+import pkg_resources
 
 system_openmc_version = pkg_resources.parse_version(openmc.__version__)
 min_openmc_version = pkg_resources.parse_version("0.14.0")
@@ -17,10 +17,11 @@
     msg = (
         "openmc_source_plotter requires openmc version 0.14.0 or above. "
         f"You have openmc version {system_openmc_version} installed. "
-        "Please update the version of openmc installed" 
+        "Please update the version of openmc installed"
     )
     raise ImportError(msg)
 
+
 def sample_initial_particles(self, n_samples: int = 1000, prn_seed: int = None):
 
     if isinstance(self, openmc.Model):