Fix Ruff lint: use lowercase parameter name for agent count

Author: nyksans

examples/energy_expenditure/model.py

@@ -85,10 +85,10 @@ class EnergyModel(Model):
     - All agents eventually die due to energy depletion
     """
 
-    def __init__(self, N=10, width=10, height=10):
+    def __init__(self, n=10, width=10, height=10):
         super().__init__()
 
-        self.num_agents = N
+        self.num_agents = n
         self.grid = MultiGrid(width, height, torus=True)
         self.schedule = RandomActivation(self)