Signature
Convert signature between r, s, v and compressed string format.
Import the bytes_to_hex_str, hex_str_to_bytes from web3py_ext
For converting {r,s,v} signature to string, define a signature in r,s,v format, use hex_str_to_bytes to convert each components to bytes
Concatenate the components in order of r + s + v and convert the result bytes to string.
For converting string signature to {r,s,v}, define a signature in string format
Convert the string signature to bytes using hex_str_to_bytes
Extract R first 32 indices, S next 32 indices, V last indice from the signature bytes
You can convert each components back to string using bytes_to_hex_str() and hex()