code: def decode_b(encoded):
      # First try encoding with validate=True, fixing the padding if needed.
      # This will succeed only if encoded includes no invalid characters.
      pad_err = len(encoded) % 4
      missing_padding = b"==="[: 4 - pad_err] if pad_err else b""
      try:
          return (
              base64.b64decode(
                  encoded + missing_padding, validate=True
              ),
              [errors.InvalidBase64PaddingDefect()] if pad_err else [],
          )
      except binascii.Error:
          # Since we had correct padding, this is likely an invalid char error.
          #
          # The non-alphabet characters are ignored as far as padding
          # goes, but we don't know how many there are.  So try without adding
          # padding to see if it works.
          try:
              return (
                  base64.b64decode(encoded, validate=False),
                  [errors.InvalidBase64CharactersDefect()],
              )
          except binascii.Error:
              # Add as much padding as could possibly be necessary (extra padding
              # is ignored).
              try:
                  return (
                      base64.b64decode(encoded + b"==", validate=False),
                      [
                          errors.InvalidBase64CharactersDefect(),
                          errors.InvalidBase64PaddingDefect(),
                      ],
                  )
              except binascii.Error:
                  # This only happens when the encoded string's length is 1 more
                  # than a multiple of 4, which is invalid.
                  #
                  # bpo-27397: Just return the encoded string since there's no
                  # way to decode.
                  return encoded, [errors.InvalidBase64LengthDefect()]
  
file_path: catboost/contrib/tools/python3/src/Lib/email/_encoded_words.py
imports: import re
  import base64
  import binascii
  import functools
  from string import ascii_letters, digits
  from email import errors
label_desc: Use image node_id 4 for calling a global function with example usage: decode_b(encoded) and returns: base64,  unknown, base64,  list, base64,  list, encoded,  list