TypeError: byte indices must be integers or slices, not str

This error occurs when you try to access a byte object using a string index. Byte objects are sequences of bytes, and their elements can only be accessed using integer indices or slices.

For example:

my_bytes = b"hello"
print(my_bytes[0])  # This will output: 104
print(my_bytes[1:3])  # This will output: b"el"
print(my_bytes["h"])  # This will raise a TypeError

In the last line of the code, we are trying to access a byte object using a string index ("h"), which is not allowed. To fix this error, you need to use integer indices or slices when accessing byte objects.