fix flake 8 error

Author: SUTIENG Tam

skypy/halos/_colossus.py

@@ -280,7 +280,7 @@ def radius(mass, concentration, redshift, mdef, Delta, cosmology, sigma8, ns):
         The scale radius in physical kpc/h.
     RDelta : float
         Spherical overdensity radius of a given mass definition Delta.
-        
+
     '''
     from colossus.cosmology.cosmology import fromAstropy
     from colossus.halo import profile_nfw