diff --git a/extract_otp_secret_keys.py b/extract_otp_secret_keys.py
index 3f1d455..14a7c4b 100644
--- a/extract_otp_secret_keys.py
+++ b/extract_otp_secret_keys.py
@@ -41,18 +41,19 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-# TODO optimze imports
 import argparse
 import base64
-import fileinput
-import sys
 import csv
+import fileinput
 import json
-from cv2 import imread, imdecode, IMREAD_UNCHANGED
-from urllib.parse import parse_qs, urlencode, urlparse, quote
-from os import path, makedirs
-from re import compile as rcompile
-from numpy import frombuffer
+import os
+import re
+import sys
+import urllib.parse as urlparse
+
+import cv2
+import numpy
+
 import protobuf_generated_python.google_auth_pb2
 
 
@@ -79,7 +80,7 @@ def main(sys_args):
 def parse_args(sys_args):
     formatter = lambda prog: argparse.HelpFormatter(prog, max_help_position=52)
     arg_parser = argparse.ArgumentParser(formatter_class=formatter)
-    arg_parser.add_argument('infile', help='1) file or - for stdin with "otpauth-migration://..." URLs separated by newlines, lines starting with # are ignored; 2) image file containing a QR code or = for stdin for an image containing a QR code', nargs='+')
+    arg_parser.add_argument('infile', help='1) file or - for stdin with "otpauth-migration://..." URLs separated by newlines, lines starting with # are ignored; or 2) image file containing a QR code or = for stdin for an image containing a QR code', nargs='+')
     arg_parser.add_argument('--json', '-j', help='export json file or - for stdout', metavar=('FILE'))
     arg_parser.add_argument('--csv', '-c', help='export csv file or - for stdout', metavar=('FILE'))
     arg_parser.add_argument('--keepass', '-k', help='export totp/hotp csv file(s) for KeePass, - for stdout', metavar=('FILE'))
@@ -180,7 +181,7 @@ def convert_img_to_line(filename):
     if verbose: print('Reading image {}'.format(filename))
     try:
         if filename != '=':
-            image = imread(filename)
+            image = cv2.imread(filename)
         else:
             try:
                 stdin = sys.stdin.buffer.read()
@@ -188,10 +189,10 @@ def convert_img_to_line(filename):
                 # Workaround for pytest, since pytest cannot monkeypatch sys.stdin.buffer
                 stdin = sys.stdin.read()
             try:
-                array = frombuffer(stdin, dtype='uint8')
+                array = numpy.frombuffer(stdin, dtype='uint8')
             except TypeError as e:
                 abort('\nERROR: Cannot read binary stdin buffer. Exception: {}'.format(str(e)))
-            image = imdecode(array, IMREAD_UNCHANGED)
+            image = cv2.imdecode(array, cv2.IMREAD_UNCHANGED)
 
         if image is None:
             abort('\nERROR: Unable to open file for reading.\ninput file: {}'.format(filename))
@@ -220,10 +221,10 @@ def get_payload_from_line(line, i, infile):
     global verbose
     if not line.startswith('otpauth-migration://'):
         eprint( '\nWARN: line is not a otpauth-migration:// URL\ninput file: {}\nline "{}"\nProbably a wrong file was given'.format(infile, line))
-    parsed_url = urlparse(line)
+    parsed_url = urlparse.urlparse(line)
     if verbose > 1: print('\nDEBUG: parsed_url={}'.format(parsed_url))
     try:
-        params = parse_qs(parsed_url.query, strict_parsing=True)
+        params = urlparse.parse_qs(parsed_url.query, strict_parsing=True)
     except:  # Not necessary for Python >= 3.11
         params = []
     if verbose > 1: print('\nDEBUG: querystring params={}'.format(params))
@@ -264,7 +265,7 @@ def build_otp_url(secret, raw_otp):
     url_params = {'secret': secret}
     if raw_otp.type == 1: url_params['counter'] = raw_otp.counter
     if raw_otp.issuer: url_params['issuer'] = raw_otp.issuer
-    otp_url = 'otpauth://{}/{}?'.format(get_otp_type_str_from_code(raw_otp.type), quote(raw_otp.name)) + urlencode( url_params)
+    otp_url = 'otpauth://{}/{}?'.format(get_otp_type_str_from_code(raw_otp.type), urlparse.quote(raw_otp.name)) + urlparse.urlencode( url_params)
     return otp_url
 
 
@@ -281,8 +282,8 @@ def print_otp(otp):
 
 def save_qr(otp, args, j):
     dir = args.saveqr
-    if not (path.exists(dir)): makedirs(dir, exist_ok=True)
-    pattern = rcompile(r'[\W_]+')
+    if not (os.path.exists(dir)): os.makedirs(dir, exist_ok=True)
+    pattern = re.compile(r'[\W_]+')
     file_otp_name = pattern.sub('', otp['name'])
     file_otp_issuer = pattern.sub('', otp['issuer'])
     save_qr_file(args, otp['url'], '{}/{}-{}{}.png'.format(dir, j, file_otp_name, '-' + file_otp_issuer if file_otp_issuer else ''))
@@ -374,7 +375,7 @@ def has_otp_type(otps, otp_type):
 
 def add_pre_suffix(file, pre_suffix):
     '''filename.ext, pre -> filename.pre.ext'''
-    name, ext = path.splitext(file)
+    name, ext = os.path.splitext(file)
     return name + "." + pre_suffix + (ext if ext else "")
 
 
@@ -394,7 +395,7 @@ def open_file_or_stdout_for_csv(filename):
 
 
 def check_file_exists(filename):
-    if filename != '-' and not path.isfile(filename):
+    if filename != '-' and not os.path.isfile(filename):
         abort('\nERROR: Input file provided is non-existent or not a file.'
         '\ninput file: {}'.format(filename))
 
diff --git a/test_extract_otp_secret_keys_pytest.py b/test_extract_otp_secret_keys_pytest.py
index 32ec68d..9cc6a66 100644
--- a/test_extract_otp_secret_keys_pytest.py
+++ b/test_extract_otp_secret_keys_pytest.py
@@ -18,13 +18,16 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-from utils import read_csv, read_csv_str, read_json, read_json_str, remove_files, remove_dir_with_files, read_file_to_str, read_binary_file_as_stream, file_exits
-from os import path
-from pytest import raises, mark
-from io import StringIO, BytesIO
-from sys import implementation, stdin
+import io
+import os
+import sys
+
+from pytest import mark, raises
 
 import extract_otp_secret_keys
+from utils import (file_exits, read_binary_file_as_stream, read_csv,
+                   read_csv_str, read_file_to_str, read_json, read_json_str,
+                   remove_dir_with_files, remove_files)
 
 
 def test_extract_stdout(capsys):
@@ -71,7 +74,7 @@ def test_extract_non_existent_file(capsys):
 
 def test_extract_stdin_stdout(capsys, monkeypatch):
     # Arrange
-    monkeypatch.setattr('sys.stdin', StringIO(read_file_to_str('example_export.txt')))
+    monkeypatch.setattr('sys.stdin', io.StringIO(read_file_to_str('example_export.txt')))
 
     # Act
     extract_otp_secret_keys.main(['-'])
@@ -85,7 +88,7 @@ def test_extract_stdin_stdout(capsys, monkeypatch):
 
 def test_extract_stdin_stdout_wrong_symbol(capsys, monkeypatch):
     # Arrange
-    monkeypatch.setattr('sys.stdin', StringIO(read_file_to_str('example_export.txt')))
+    monkeypatch.setattr('sys.stdin', io.StringIO(read_file_to_str('example_export.txt')))
 
     # Act
     with raises(SystemExit) as e:
@@ -149,7 +152,7 @@ def test_extract_csv_stdout(capsys):
 def test_extract_stdin_and_csv_stdout(capsys, monkeypatch):
     # Arrange
     cleanup()
-    monkeypatch.setattr('sys.stdin', StringIO(read_file_to_str('example_export.txt')))
+    monkeypatch.setattr('sys.stdin', io.StringIO(read_file_to_str('example_export.txt')))
 
     # Act
     extract_otp_secret_keys.main(['-c', '-', '-'])
@@ -347,16 +350,16 @@ def test_extract_saveqr(capsys):
     assert captured.out == ''
     assert captured.err == ''
 
-    assert path.isfile('testout/qr/1-piraspberrypi-raspberrypi.png')
-    assert path.isfile('testout/qr/2-piraspberrypi.png')
-    assert path.isfile('testout/qr/3-piraspberrypi.png')
-    assert path.isfile('testout/qr/4-piraspberrypi-raspberrypi.png')
+    assert os.path.isfile('testout/qr/1-piraspberrypi-raspberrypi.png')
+    assert os.path.isfile('testout/qr/2-piraspberrypi.png')
+    assert os.path.isfile('testout/qr/3-piraspberrypi.png')
+    assert os.path.isfile('testout/qr/4-piraspberrypi-raspberrypi.png')
 
     # Clean up
     cleanup()
 
 
-@mark.skipif(implementation.name == 'pypy', reason="Encoding problems in verbose mode in pypy.")
+@mark.skipif(sys.implementation.name == 'pypy', reason="Encoding problems in verbose mode in pypy.")
 def test_extract_verbose(capsys):
     # Act
     extract_otp_secret_keys.main(['-v', 'example_export.txt'])
diff --git a/test_extract_otp_secret_keys_unittest.py b/test_extract_otp_secret_keys_unittest.py
index 76cc9c9..874ef09 100644
--- a/test_extract_otp_secret_keys_unittest.py
+++ b/test_extract_otp_secret_keys_unittest.py
@@ -22,8 +22,8 @@ import unittest
 import io
 from contextlib import redirect_stdout
 from utils import read_csv, read_json, remove_file, remove_dir_with_files, Capturing, read_file_to_str
-from os import path
-from sys import implementation
+import os
+import sys
 
 import extract_otp_secret_keys
 
@@ -160,13 +160,13 @@ Type:    totp
     def test_extract_saveqr(self):
         extract_otp_secret_keys.main(['-q', '-s', 'testout/qr/', 'example_export.txt'])
 
-        self.assertTrue(path.isfile('testout/qr/1-piraspberrypi-raspberrypi.png'))
-        self.assertTrue(path.isfile('testout/qr/2-piraspberrypi.png'))
-        self.assertTrue(path.isfile('testout/qr/3-piraspberrypi.png'))
-        self.assertTrue(path.isfile('testout/qr/4-piraspberrypi-raspberrypi.png'))
+        self.assertTrue(os.path.isfile('testout/qr/1-piraspberrypi-raspberrypi.png'))
+        self.assertTrue(os.path.isfile('testout/qr/2-piraspberrypi.png'))
+        self.assertTrue(os.path.isfile('testout/qr/3-piraspberrypi.png'))
+        self.assertTrue(os.path.isfile('testout/qr/4-piraspberrypi-raspberrypi.png'))
 
     def test_extract_verbose(self):
-        if implementation.name == 'pypy': self.skipTest("Encoding problems in verbose mode in pypy.")
+        if sys.implementation.name == 'pypy': self.skipTest("Encoding problems in verbose mode in pypy.")
         out = io.StringIO()
         with redirect_stdout(out):
             extract_otp_secret_keys.main(['-v', 'example_export.txt'])
diff --git a/utils.py b/utils.py
index 227d746..ffd86e5 100644
--- a/utils.py
+++ b/utils.py
@@ -17,7 +17,7 @@ import csv
 import json
 import os
 import shutil
-from io import StringIO, BytesIO
+import io
 import sys
 import glob
 
@@ -31,9 +31,9 @@ with Capturing() as output:
 '''
     def __enter__(self):
         self._stdout = sys.stdout
-        sys.stdout = self._stringio_std = StringIO()
+        sys.stdout = self._stringio_std = io.StringIO()
         self._stderr = sys.stderr
-        sys.stderr = self._stringio_err = StringIO()
+        sys.stderr = self._stringio_err = io.StringIO()
         return self
 
     def __exit__(self, *args):
@@ -106,4 +106,4 @@ def read_file_to_str(filename):
 def read_binary_file_as_stream(filename):
     """Returns binary file content."""
     with open(filename, "rb",) as infile:
-        return BytesIO(infile.read())
+        return io.BytesIO(infile.read())