diff --git a/dartwrf/assim_synth_obs.py b/dartwrf/assim_synth_obs.py
index 2d5db6956d8fddf709e5f0d09678709967d9ca40..bc96d642b30ce21a009e34698c77f44da3a49f2b 100755
--- a/dartwrf/assim_synth_obs.py
+++ b/dartwrf/assim_synth_obs.py
@@ -5,10 +5,10 @@ import numpy as np
 
 from config.cfg import exp, cluster
 from dartwrf.utils import symlink, copy, sed_inplace, append_file, mkdir, try_remove, print, shell
+from dartwrf.obs import error_models as err
 import dartwrf.create_obsseq as osq
 from dartwrf import wrfout_add_geo
 from dartwrf import obsseq
-from dartwrf.obs import error_models as err
 
 earth_radius_km = 6370
 
diff --git a/dartwrf/create_obsseq.py b/dartwrf/create_obsseq.py
index 9581d664d2cf45c5e798c827291da5f485b38d7b..2b2e9c47d31cf06deed6e2b25c42057eabf2d971 100755
--- a/dartwrf/create_obsseq.py
+++ b/dartwrf/create_obsseq.py
@@ -237,8 +237,8 @@ def create_obs_seq_in(time_dt, list_obscfg,
 
         assert len(coords) == n_obs, (len(coords), n_obs)  # check if functions did what they supposed to
         for lat, lon in coords:
-            assert lat < 90 & lat > -90
-            assert lon < 180 & lon > -180
+            assert (lat < 90) & (lat > -90)
+            assert (lon < 180) & (lon > -180)
 
         kind = obscfg['kind']
         print('obstype', kind)
diff --git a/dartwrf/evaluate_posterior.py b/dartwrf/evaluate_posterior.py
index e1e24a444ae5fd7a6d6b95b39ca75dc781a8b4ee..66e7ea28830b4aad5d1fd27cf36ee934c089e2b0 100755
--- a/dartwrf/evaluate_posterior.py
+++ b/dartwrf/evaluate_posterior.py
@@ -7,7 +7,6 @@ from config.cfg import exp, cluster
 from dartwrf import assim_synth_obs as aso
 
 
-
 if __name__ == "__main__":
 
      assim_time = dt.datetime.strptime(sys.argv[1], "%Y-%m-%d_%H:%M")
diff --git a/dartwrf/evaluate_prior.py b/dartwrf/evaluate_prior.py
index 0e0ec66974b25149277673e488ca1995232f9b98..43a4388654edd5ad4181571c54ef7e332b66e6b6 100755
--- a/dartwrf/evaluate_prior.py
+++ b/dartwrf/evaluate_prior.py
@@ -6,6 +6,7 @@ import numpy as np
 from config.cfg import exp, cluster
 from dartwrf.utils import symlink, copy, sed_inplace, append_file, mkdir, try_remove, print, shell
 from dartwrf import assim_synth_obs as aso
+
 from osselyze.utils import get_prior_config
 
 if __name__ == "__main__":
diff --git a/dartwrf/obsseq_to_netcdf.py b/dartwrf/obsseq_to_netcdf.py
index ad41ffdcff262df1b52352c6396218311140b292..43feeda18da410fca88b1e7535963ff8dbb3a37d 100644
--- a/dartwrf/obsseq_to_netcdf.py
+++ b/dartwrf/obsseq_to_netcdf.py
@@ -1,4 +1,5 @@
 import os, sys, glob, warnings
+
 from config.cfg import exp, cluster
 import run_obs_diag as rod
 
diff --git a/dartwrf/prepare_namelist.py b/dartwrf/prepare_namelist.py
index 4f2672b68204ad8963d27b2ed3fb4b5c3478524b..71cc747435ca6225ef471c8364b92b44d696820b 100755
--- a/dartwrf/prepare_namelist.py
+++ b/dartwrf/prepare_namelist.py
@@ -11,6 +11,7 @@ Options:
 import os, sys, shutil, warnings
 import datetime as dt
 from docopt import docopt
+
 from config.cfg import exp, cluster
 from utils import sed_inplace, copy, symlink, mkdir
 
diff --git a/dartwrf/run_obs_diag.py b/dartwrf/run_obs_diag.py
index fb327b5814be4e9d8d2172778ea76a05639643c2..54991039f9a1d0719279c971e7652c14ccb68bea 100644
--- a/dartwrf/run_obs_diag.py
+++ b/dartwrf/run_obs_diag.py
@@ -1,10 +1,10 @@
 import os, sys, shutil, glob
+
 from config.cfg import exp, cluster
 from utils import symlink, copy, sed_inplace, append_file, shell
 
 rundir_program = '/home/fs71386/lkugler/data/run_DART/'
 
-
 def prepare(obserr_iszero='.true.'):
     copy(cluster.scriptsdir+'/../templates/input.eval.nml',
             rundir_program+'/input.nml')
diff --git a/dartwrf/wrfout_add_geo.py b/dartwrf/wrfout_add_geo.py
index 08e61271ffa40144a89071fa7b521575bf3cda02..e399dcf09b72ed9c945f67b47b379f28ef986846 100755
--- a/dartwrf/wrfout_add_geo.py
+++ b/dartwrf/wrfout_add_geo.py
@@ -9,6 +9,7 @@ Example call:
 """
 import os, sys
 import netCDF4 as nc
+
 from config.cfg import exp, cluster
 
 fields_old = ["XLAT_M",   "XLONG_M",      "CLAT",