start removal of six and improve type annotation (#607)

* fix unfinished Python2 -> 3 translation
* remove some six usage
* annotate
* fix regression in Six removal
* mypy: self.enf is always defined
* fix return type of cups.py
* Usb idVendor/idProduct are integers
* self.default_args is always defined
* tweak usb_args, PEP589 is better
* lp.py: reassure mypy
* correctly cast call to CashDrawerError()
* update CUPS test
* add missing close() method in metaclass
* document a bug in typeshed
* query_status() returns bytes as seen in constants.py
* remove more SIX usage
* test examples too
* remove type comment where type is annotated
* adapt behavior of cups printer to match other implementations

---------

Co-authored-by: Patrick Kanzler <dev@pkanzler.de>
Co-authored-by: Patrick Kanzler <4189642+patkan@users.noreply.github.com>

test/test_function_set.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 import pytest
 import six
 
@@ -6,7 +8,7 @@ from escpos.constants import SET_FONT, TXT_NORMAL, TXT_SIZE, TXT_STYLE
 from escpos.exceptions import SetVariableError
 
 
-def test_default_values_with_default():
+def test_default_values_with_default() -> None:
     """Default test, please copy and paste this block to test set method calls"""
     instance = printer.Dummy()
     instance.set_with_default()
@@ -26,7 +28,7 @@ def test_default_values_with_default():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_default_values():
+def test_default_values() -> None:
     """Default test"""
     instance = printer.Dummy()
     instance.set()
@@ -37,7 +39,7 @@ def test_default_values():
 # Size tests
 
 
-def test_set_size_2h():
+def test_set_size_2h() -> None:
     instance = printer.Dummy()
     instance.set_with_default(double_height=True)
 
@@ -56,7 +58,7 @@ def test_set_size_2h():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_size_2h_no_default():
+def test_set_size_2h_no_default() -> None:
     instance = printer.Dummy()
     instance.set(double_height=True)
 
@@ -68,7 +70,7 @@ def test_set_size_2h_no_default():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_size_2w():
+def test_set_size_2w() -> None:
     instance = printer.Dummy()
     instance.set_with_default(double_width=True)
 
@@ -87,7 +89,7 @@ def test_set_size_2w():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_size_2w_no_default():
+def test_set_size_2w_no_default() -> None:
     instance = printer.Dummy()
     instance.set(double_width=True)
 
@@ -99,7 +101,7 @@ def test_set_size_2w_no_default():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_size_2x():
+def test_set_size_2x() -> None:
     instance = printer.Dummy()
     instance.set_with_default(double_height=True, double_width=True)
 
@@ -118,7 +120,7 @@ def test_set_size_2x():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_size_2x_no_default():
+def test_set_size_2x_no_default() -> None:
     instance = printer.Dummy()
     instance.set(double_width=True, double_height=True)
 
@@ -130,7 +132,7 @@ def test_set_size_2x_no_default():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_size_custom():
+def test_set_size_custom() -> None:
     instance = printer.Dummy()
     instance.set_with_default(custom_size=True, width=8, height=7)
 
@@ -151,7 +153,7 @@ def test_set_size_custom():
 
 @pytest.mark.parametrize("width", [1, 8])
 @pytest.mark.parametrize("height", [1, 8])
-def test_set_size_custom_no_default(width, height):
+def test_set_size_custom_no_default(width: int, height: int) -> None:
     instance = printer.Dummy()
     instance.set(custom_size=True, width=width, height=height)
 
@@ -165,7 +167,9 @@ def test_set_size_custom_no_default(width, height):
 
 @pytest.mark.parametrize("width", [None, 0, 9, 10, 4444])
 @pytest.mark.parametrize("height", [None, 0, 9, 10, 4444])
-def test_set_size_custom_invalid_input(width, height):
+def test_set_size_custom_invalid_input(
+    width: Optional[int], height: Optional[int]
+) -> None:
     instance = printer.Dummy()
     with pytest.raises(SetVariableError):
         instance.set(custom_size=True, width=width, height=height)
@@ -174,7 +178,7 @@ def test_set_size_custom_invalid_input(width, height):
 # Flip
 
 
-def test_set_flip():
+def test_set_flip() -> None:
     instance = printer.Dummy()
     instance.set_with_default(flip=True)
 
@@ -193,7 +197,7 @@ def test_set_flip():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_flip_no_default():
+def test_set_flip_no_default() -> None:
     instance = printer.Dummy()
     instance.set(flip=True)
 
@@ -205,7 +209,7 @@ def test_set_flip_no_default():
 # Smooth
 
 
-def test_smooth():
+def test_smooth() -> None:
     instance = printer.Dummy()
     instance.set_with_default(smooth=True)
 
@@ -227,7 +231,7 @@ def test_smooth():
 # Type
 
 
-def test_set_bold():
+def test_set_bold() -> None:
     instance = printer.Dummy()
     instance.set_with_default(bold=True)
 
@@ -246,7 +250,7 @@ def test_set_bold():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_underline():
+def test_set_underline() -> None:
     instance = printer.Dummy()
     instance.set_with_default(underline=1)
 
@@ -265,7 +269,7 @@ def test_set_underline():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_set_underline2():
+def test_set_underline2() -> None:
     instance = printer.Dummy()
     instance.set_with_default(underline=2)
 
@@ -287,7 +291,7 @@ def test_set_underline2():
 # Align
 
 
-def test_align_center():
+def test_align_center() -> None:
     instance = printer.Dummy()
     instance.set_with_default(align="center")
 
@@ -306,7 +310,7 @@ def test_align_center():
     assert instance.output == b"".join(expected_sequence)
 
 
-def test_align_right():
+def test_align_right() -> None:
     instance = printer.Dummy()
     instance.set_with_default(align="right")
 
@@ -328,7 +332,7 @@ def test_align_right():
 # Densities
 
 
-def test_densities():
+def test_densities() -> None:
     for density in range(8):
         instance = printer.Dummy()
         instance.set_with_default(density=density)
@@ -352,7 +356,7 @@ def test_densities():
 # Invert
 
 
-def test_invert():
+def test_invert() -> None:
     instance = printer.Dummy()
     instance.set_with_default(invert=True)