diff --git a/doc/api/config.rst b/doc/api/config.rst
index c5e3691..ab17067 100644
--- a/doc/api/config.rst
+++ b/doc/api/config.rst
@@ -1,5 +1,5 @@
 Config
----------
+------
 Module :py:mod:`escpos.config`
 
 .. automodule:: escpos.config
diff --git a/escpos/escpos.py b/escpos/escpos.py
index 33c73e2..435b95e 100644
--- a/escpos/escpos.py
+++ b/escpos/escpos.py
@@ -238,12 +238,12 @@ class Escpos(object):
 
         (width, height) = image.size
         self._raw(S_RASTER_N)
-        headerX = int(width / 8)
-        headerY = height
-        buf = "{0:02X}".format((headerX & 0xff))
-        buf += "{0:02X}".format(((headerX >> 8) & 0xff))
-        buf += "{0:02X}".format((headerY & 0xff))
-        buf += "{0:02X}".format(((headerY >> 8) & 0xff))
+        header_x = int(width / 8)
+        header_y = height
+        buf = "{0:02X}".format((header_x & 0xff))
+        buf += "{0:02X}".format(((header_x >> 8) & 0xff))
+        buf += "{0:02X}".format((header_y & 0xff))
+        buf += "{0:02X}".format(((header_y >> 8) & 0xff))
         #self._raw(binascii.unhexlify(buf))
         for y in range(height):
             for x in range(width):
@@ -550,8 +550,8 @@ class Escpos(object):
         :param columns: amount of columns
         :return: None
         """
-        colCount = self.columns if columns is None else columns
-        self.text(textwrap.fill(txt, colCount))
+        col_count = self.columns if columns is None else columns
+        self.text(textwrap.fill(txt, col_count))
 
     def set(self, align='left', font='a', text_type='normal', width=1, height=1, density=9, invert=False, smooth=False, flip=False):
         """ Set text properties by sending them to the printer
@@ -733,7 +733,7 @@ class Escpos(object):
         :raises: :py:exc:`~escpos.exceptions.TabPosError`
         """
         # Set tab positions
-        if pos < 1 or pos > 16:
+        if not (1 <= pos <= 16):
             raise TabPosError()
         else:
             self._raw(CTL_SET_HT + six.int2byte(pos))
diff --git a/escpos/printer.py b/escpos/printer.py
index 5a4d126..ddd6ae5 100644
--- a/escpos/printer.py
+++ b/escpos/printer.py
@@ -17,7 +17,7 @@ import usb.util
 import serial
 import socket
 
-from .escpos import *
+from .escpos import Escpos
 from .exceptions import *
 
 
diff --git a/test/test_cli.py b/test/test_cli.py
index 331eff6..03beb2d 100644
--- a/test/test_cli.py
+++ b/test/test_cli.py
@@ -28,6 +28,7 @@ printer:
     testfile=DEVFILE,
 )
 
+
 class TestCLI:
     """ Contains setups, teardowns, and tests for CLI
     """
diff --git a/test/test_function_text.py b/test/test_function_text.py
index 2ad7bd1..b0b1ca1 100644
--- a/test/test_function_text.py
+++ b/test/test_function_text.py
@@ -21,6 +21,7 @@ import filecmp
 
 devfile = 'testfile'
 
+
 def setup_testfile():
     """create a testfile as devfile"""
     fhandle = open(devfile, 'a')
@@ -29,10 +30,12 @@ def setup_testfile():
     finally:
         fhandle.close()
 
+
 def teardown_testfile():
     """destroy testfile again"""
     os.remove(devfile)
 
+
 @with_setup(setup_testfile, teardown_testfile)
 def test_function_text_dies_ist_ein_test_lf():
     """test the text printing function with simple string and compare output"""
diff --git a/test/test_load_module.py b/test/test_load_module.py
index 0cfcce9..daf94b4 100644
--- a/test/test_load_module.py
+++ b/test/test_load_module.py
@@ -19,6 +19,7 @@ import os
 
 devfile = 'testfile'
 
+
 def setup_testfile():
     """create a testfile as devfile"""
     fhandle = open(devfile, 'a')
@@ -27,10 +28,12 @@ def setup_testfile():
     finally:
         fhandle.close()
 
+
 def teardown_testfile():
     """destroy testfile again"""
     os.remove(devfile)
 
+
 @with_setup(setup_testfile, teardown_testfile)
 def test_instantiation():
     """test the instantiation of a escpos-printer class and basic printing"""