whitespaces empty lines

src/sage/combinat/nu_tamari_lattice.py

@@ -229,7 +229,7 @@
     REFERENCES:
 
     - [PRV2017]_
-    
+
     - [CC2023]_
     """
     if not( (isinstance(nu, (list, tuple)) and all(x in [0, 1] for x in nu)) or
@@ -243,7 +243,7 @@
     if delta is None:
         delta = deltamax
     elif len(delta) != len(deltamax) or any([delta[i] > deltamax[i] for i in range(len(delta))]):
         raise ValueError("delta is not a valid increment vector")
 
     def covers(p):
         return [delta_swap(p, k, delta=delta) for k in range(1, p.length())