hot-fix for the linter

Author: fchapoton

src/sage/features/info.py

@@ -5,6 +5,7 @@
 
 from . import Executable
 
+
 class Info(Executable):
     r"""
     A :class:`~sage.features.Feature` describing the presence of :ref:`info <spkg_info>`.
@@ -26,5 +27,6 @@ def __init__(self):
         Executable.__init__(self, 'info', executable='info',
                             spkg='info', type='standard')
 
+
 def all_features():
     return [Info()]

src/sage/matroids/chow_ring_ideal.py

@@ -13,6 +13,7 @@
 from sage.combinat.posets.posets import Poset
 from itertools import product
 
+
 class ChowRingIdeal(MPolynomialIdeal):
     def matroid(self):
         r"""
@@ -55,6 +56,7 @@ def _lattice_flats(self):
         chains = lattice_flats.chains()  #Only chains
         return (ranks, chains)
 
+
 class ChowRingIdeal_nonaug(ChowRingIdeal):
     r"""
     The Chow ring ideal of a matroid `M`.
@@ -797,4 +799,4 @@ def normal_basis(self, algorithm='', *args, **kwargs):
                         for val, c in zip(subset, combination):
                             expression *= flats_gen[val] ** c
                         monomial_basis.append(expression)
-        return PolynomialSequence(R, [monomial_basis])
+        return PolynomialSequence(R, [monomial_basis])

src/sage/rings/semirings/tropical_variety.py

@@ -32,6 +32,7 @@
 from sage.rings.rational_field import QQ
 from sage.rings.infinity import infinity
 
+
 class TropicalVariety(UniqueRepresentation, SageObject):
     r"""
     A tropical variety in `\RR^n`.