diff --git a/src/domain_tuple.py b/src/domain_tuple.py
index 84df832ca7a6a7c38a808f7048355fad9d113181..456c5d3924a3f367826959454e43b05f33a31ba0 100644
--- a/src/domain_tuple.py
+++ b/src/domain_tuple.py
@@ -16,11 +16,12 @@
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
 from functools import reduce
-from . import utilities
-from .domains.domain import Domain
 
 import numpy as np
 
+from . import utilities
+from .domains.domain import Domain
+
 
 class DomainTuple(object):
     """Ordered sequence of Domain objects.
diff --git a/src/domains/domain.py b/src/domains/domain.py
index a5bed83066c2ad43797d58a95b2d12391aed9179..92ea0201766c07144b7989071be2af8c318dbb9c 100644
--- a/src/domains/domain.py
+++ b/src/domains/domain.py
@@ -16,6 +16,7 @@
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
 from functools import reduce
+
 from ..utilities import NiftyMeta
 
 
diff --git a/src/domains/rg_space.py b/src/domains/rg_space.py
index 4adc200c63b7137a36d3c452dbf162486abd6d18..20f2adc7dbb9eda1d3040e582e032ed5d4378dd7 100644
--- a/src/domains/rg_space.py
+++ b/src/domains/rg_space.py
@@ -16,6 +16,7 @@
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
 from functools import reduce
+
 import numpy as np
 
 from ..field import Field
diff --git a/src/domains/unstructured_domain.py b/src/domains/unstructured_domain.py
index baf4ea077261c72516c9c79bb9b4dfb3f2c69f53..218dfe940d287371b71deb9930b1927ef85b0000 100644
--- a/src/domains/unstructured_domain.py
+++ b/src/domains/unstructured_domain.py
@@ -16,6 +16,7 @@
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
 from functools import reduce
+
 from .domain import Domain
 
 
diff --git a/src/field.py b/src/field.py
index 5ddb1df52ebb2adede19ec88286938b0657d88f3..ec30aad00e977db8a4c8755380867cc80d97b2d0 100644
--- a/src/field.py
+++ b/src/field.py
@@ -16,6 +16,7 @@
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
 from functools import reduce
+
 import numpy as np
 
 from . import utilities
diff --git a/src/library/correlated_fields.py b/src/library/correlated_fields.py
index 8dacfc264f637ece56e00f6ebc19d1f3d627a2f1..8f11ab6983f641d0dfcf0472d57d72ae40324132 100644
--- a/src/library/correlated_fields.py
+++ b/src/library/correlated_fields.py
@@ -21,6 +21,7 @@ from operator import mul
 
 import numpy as np
 
+from .. import utilities
 from ..domain_tuple import DomainTuple
 from ..domains.power_space import PowerSpace
 from ..domains.unstructured_domain import UnstructuredDomain
@@ -38,7 +39,6 @@ from ..operators.operator import Operator
 from ..operators.simple_linear_operators import ducktape
 from ..probing import StatCalculator
 from ..sugar import full, makeDomain, makeField, makeOp
-from .. import utilities
 
 
 def _reshaper(x, N):
diff --git a/src/library/gridder.py b/src/library/gridder.py
index 1af2d314c2186a8870254b732b2bf95f6ea3f13b..595ba25d07f859c4fab39d3fe26b61785f604fb2 100644
--- a/src/library/gridder.py
+++ b/src/library/gridder.py
@@ -21,7 +21,7 @@ from ..domain_tuple import DomainTuple
 from ..domains.rg_space import RGSpace
 from ..domains.unstructured_domain import UnstructuredDomain
 from ..operators.linear_operator import LinearOperator
-from ..sugar import makeField, makeDomain
+from ..sugar import makeDomain, makeField
 
 
 class GridderMaker(object):
diff --git a/src/library/special_distributions.py b/src/library/special_distributions.py
index c06b15beca3076792e6b31d4d31dee368a8959f2..49b37ca61b94b3d50b5c0ceaa0d401e41c7c1150 100644
--- a/src/library/special_distributions.py
+++ b/src/library/special_distributions.py
@@ -16,15 +16,15 @@
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
 import numpy as np
-from scipy.stats import invgamma, norm
 from scipy.interpolate import CubicSpline
+from scipy.stats import invgamma, norm
 
+from .. import random
 from ..domain_tuple import DomainTuple
 from ..domains.unstructured_domain import UnstructuredDomain
 from ..field import Field
 from ..operators.operator import Operator
 from ..sugar import makeOp
-from .. import random
 
 
 def _f_on_np(f, arr):
diff --git a/src/linearization.py b/src/linearization.py
index 5286e9e2afe9ac86c7801c4ed43d7298e282b378..9140993567a8f79ad884421bccda0007e25914c2 100644
--- a/src/linearization.py
+++ b/src/linearization.py
@@ -17,8 +17,8 @@
 
 import numpy as np
 
-from .sugar import makeOp
 from .operators.operator import Operator
+from .sugar import makeOp
 
 
 class Linearization(Operator):
diff --git a/src/minimization/line_search.py b/src/minimization/line_search.py
index 7aa4af3276ca5c362249bb467423cd9ce1dce544..590cdb86252a1ba89ffb8b8d5c9227e9233699ef 100644
--- a/src/minimization/line_search.py
+++ b/src/minimization/line_search.py
@@ -15,10 +15,11 @@
 #
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
-from ..utilities import NiftyMeta
-from ..logger import logger
 import numpy as np
 
+from ..logger import logger
+from ..utilities import NiftyMeta
+
 
 class LineEnergy(object):
     """Evaluates an underlying Energy along a certain line direction.
diff --git a/src/multi_field.py b/src/multi_field.py
index 1051aaec7cd49a96e46e4f00c58c4257c81dd7df..6d54a1f91b7f134df4613fb2ac997b29674b9f0c 100644
--- a/src/multi_field.py
+++ b/src/multi_field.py
@@ -18,9 +18,9 @@
 import numpy as np
 
 from . import utilities
+from .domain_tuple import DomainTuple
 from .field import Field
 from .multi_domain import MultiDomain
-from .domain_tuple import DomainTuple
 from .operators.operator import Operator
 
 
diff --git a/src/operator_spectrum.py b/src/operator_spectrum.py
index 4c3ff20457877472a90f338f03716fe5761990d7..7954ca2a93977617dd64f1b339093efa9c86f074 100644
--- a/src/operator_spectrum.py
+++ b/src/operator_spectrum.py
@@ -23,7 +23,7 @@ from .multi_domain import MultiDomain
 from .multi_field import MultiField
 from .operators.linear_operator import LinearOperator
 from .operators.sandwich_operator import SandwichOperator
-from .sugar import makeField, makeDomain
+from .sugar import makeDomain, makeField
 
 
 class _DomRemover(LinearOperator):
diff --git a/src/operator_tree_optimiser.py b/src/operator_tree_optimiser.py
index 97b08349abda7608c0daaf220f046ddb7f2a41f1..85dedfc422dbb47a246432416ed984e332ca59fe 100644
--- a/src/operator_tree_optimiser.py
+++ b/src/operator_tree_optimiser.py
@@ -15,9 +15,15 @@
 #
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
-from .operators.operator import _OpChain, _OpSum, _OpProd
-from .sugar import domain_union
+from copy import deepcopy
+
+from numpy import allclose
+
+from .multi_field import MultiField
+from .operators.operator import _OpChain, _OpProd, _OpSum
 from .operators.simple_linear_operators import FieldAdapter
+from .sugar import domain_union, from_random
+
 
 def _optimise_operator(op):
     """
@@ -260,10 +266,6 @@ def _optimise_operator(op):
     return op
 
 
-from copy import deepcopy
-from .sugar import from_random
-from .multi_field import MultiField
-from numpy import allclose
 
 
 def optimise_operator(op):
diff --git a/src/operators/block_diagonal_operator.py b/src/operators/block_diagonal_operator.py
index 34f6ffca36fd8ea3e0099d8cedb8d5171cb3a7dc..3e596942f509c45f46cb19621ec7da7c0084b322 100644
--- a/src/operators/block_diagonal_operator.py
+++ b/src/operators/block_diagonal_operator.py
@@ -20,6 +20,7 @@ from ..multi_field import MultiField
 from .endomorphic_operator import EndomorphicOperator
 from .linear_operator import LinearOperator
 
+
 class BlockDiagonalOperator(EndomorphicOperator):
     """
     Parameters
diff --git a/src/operators/matrix_product_operator.py b/src/operators/matrix_product_operator.py
index 66357de1b0248cc4b1fecf0b29dbfc5dcb93cbe0..b9fa34300eade7044939339e5b80c8678fe90398 100644
--- a/src/operators/matrix_product_operator.py
+++ b/src/operators/matrix_product_operator.py
@@ -15,11 +15,12 @@
 #
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
+import numpy as np
+
+from .. import utilities
 from ..domain_tuple import DomainTuple
 from ..field import Field
 from .endomorphic_operator import EndomorphicOperator
-from .. import utilities
-import numpy as np
 
 
 class MatrixProductOperator(EndomorphicOperator):
diff --git a/src/operators/operator.py b/src/operators/operator.py
index a01044e9d5d301051774633872c4f4cff4cd365d..4319debb4337804f71ac5a93df2274b7ee6c5088 100644
--- a/src/operators/operator.py
+++ b/src/operators/operator.py
@@ -17,8 +17,8 @@
 
 import numpy as np
 
-from ..utilities import NiftyMeta, indent
 from .. import pointwise
+from ..utilities import NiftyMeta, indent
 
 
 class Operator(metaclass=NiftyMeta):
diff --git a/src/operators/partial_conjugate.py b/src/operators/partial_conjugate.py
index 9cdf9aa9733ceaeb08ec94b91ba7ddd532efad5f..48e6ad0ccba31a68962268ee612a4217f93cdce0 100644
--- a/src/operators/partial_conjugate.py
+++ b/src/operators/partial_conjugate.py
@@ -16,9 +16,10 @@
 #
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
-from .endomorphic_operator import EndomorphicOperator
 from ..multi_domain import MultiDomain
 from ..multi_field import MultiField
+from .endomorphic_operator import EndomorphicOperator
+
 
 class PartialConjugate(EndomorphicOperator):
     """Perform partial conjugation of a :class:`MultiField`
diff --git a/src/operators/selection_operators.py b/src/operators/selection_operators.py
index 6c8714b1c3d91d9649f860c0af5c808f87f994ad..ce1304068e916843759d8bfc84827d57b5bcee26 100644
--- a/src/operators/selection_operators.py
+++ b/src/operators/selection_operators.py
@@ -17,6 +17,7 @@
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
 import numpy as np
+
 from ..domain_tuple import DomainTuple
 from ..domains.rg_space import RGSpace
 from ..domains.unstructured_domain import UnstructuredDomain
diff --git a/src/probing.py b/src/probing.py
index 46968ae8c2d26d8953947e338bac032dc22576b0..4f224cc651e4db4520308624bf6e5cd24cd6103f 100644
--- a/src/probing.py
+++ b/src/probing.py
@@ -18,7 +18,7 @@
 from .multi_field import MultiField
 from .operators.endomorphic_operator import EndomorphicOperator
 from .operators.operator import Operator
-from .sugar import makeField, from_random
+from .sugar import from_random, makeField
 
 
 class StatCalculator(object):
diff --git a/src/utilities.py b/src/utilities.py
index 008fa0ec9f51e824e26d2f5ba75b348f03d9fa13..d7f71a712d62d4988fa3b2ed01aa166a8fe55cfe 100644
--- a/src/utilities.py
+++ b/src/utilities.py
@@ -16,8 +16,8 @@
 # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
 
 import collections
-from itertools import product
 from functools import reduce
+from itertools import product
 
 import numpy as np