code: def test_b64decode(self):
      eq = self.assertEqual
  
      tests = {
          b"d3d3LnB5dGhvbi5vcmc=": b"www.python.org",
          b"AA==": b"\x00",
          b"YQ==": b"a",
          b"YWI=": b"ab",
          b"YWJj": b"abc",
          b"YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXpBQkNE"
          b"RUZHSElKS0xNTk9QUVJTVFVWV1hZWjAxMjM0\nNT"
          b"Y3ODkhQCMwXiYqKCk7Ojw+LC4gW117fQ==": b"abcdefghijklmnopqrstuvwxyz"
          b"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
          b"0123456789!@#0^&*();:<>,. []{}",
          b"": b"",
      }
      for data, res in tests.items():
          eq(base64.b64decode(data), res)
          eq(base64.b64decode(data.decode("ascii")), res)
      # Non-bytes
      self.check_other_types(base64.b64decode, b"YWJj", b"abc")
      self.check_decode_type_errors(base64.b64decode)
  
      # Test with arbitrary alternative characters
      tests_altchars = {
          (b"01a*b$cd", b"*$"): b"\xd3V\xbeo\xf7\x1d",
      }
      for (data, altchars), res in tests_altchars.items():
          data_str = data.decode("ascii")
          altchars_str = altchars.decode("ascii")
  
          eq(base64.b64decode(data, altchars=altchars), res)
          eq(base64.b64decode(data_str, altchars=altchars), res)
          eq(base64.b64decode(data, altchars=altchars_str), res)
          eq(base64.b64decode(data_str, altchars=altchars_str), res)
  
      # Test standard alphabet
      for data, res in tests.items():
          eq(base64.standard_b64decode(data), res)
          eq(base64.standard_b64decode(data.decode("ascii")), res)
      # Non-bytes
      self.check_other_types(base64.standard_b64decode, b"YWJj", b"abc")
      self.check_decode_type_errors(base64.standard_b64decode)
  
      # Test with 'URL safe' alternative characters
      tests_urlsafe = {
          b"01a-b_cd": b"\xd3V\xbeo\xf7\x1d",
          b"": b"",
      }
      for data, res in tests_urlsafe.items():
          eq(base64.urlsafe_b64decode(data), res)
          eq(base64.urlsafe_b64decode(data.decode("ascii")), res)
      # Non-bytes
      self.check_other_types(
          base64.urlsafe_b64decode, b"01a-b_cd", b"\xd3V\xbeo\xf7\x1d"
      )
      self.check_decode_type_errors(base64.urlsafe_b64decode)
  
imports: import unittest
  import base64
  import binascii
  import os
  from array import array
  from test.support import os_helper
  from test.support import script_helper
label_desc: Use image node_id 7 for calling the BaseXYTestCase obj's underlying member method code with example usage: obj.test_b64decode() without return types