diff --git a/pmd_beamphysics/particles.py b/pmd_beamphysics/particles.py
index 5f0361f..2d150fe 100644
--- a/pmd_beamphysics/particles.py
+++ b/pmd_beamphysics/particles.py
@@ -1143,8 +1143,8 @@ def fractional_split(self, fractions: Union[float, int, list], key: str):
         """
         Split particles based on a given array key and a list of specified fractions or a single fraction.
 
-        Parameters:
-        -----------
+        Parameters
+        ----------
         fractions : float, int, or list of float/int
             A fraction or a list of fractions used for splitting the particles. All values must be between 0 and 1 (exclusive).