Search for bytes that are located before a set of found bytes

[random_1]

Im trying to find for bytes(unknown) that appear before another set of bytes that have already been found. i have a binary file that for example looks like this:

82 00 10 00 00 00 00 00 00 00 00 00 00 01 00 00
60 F8 6C 10 BF 58 87 45 87 6F 0C 61 0D 26 B0 F5
10 00 00 00 01 00 11 00 00 00 00 00 0E 00 11 00
2D 00 04 00 72 46 13 F4 18 43 C0 D2 0A 64 24 91
F3 E7 00 80 54 00 4E B2 61 00 00 08 00 00 00 00

the bytes that i know (the value and position of) is 0A 64 24 91 F3 E7, by using this (bytes1 is inputed by user):

bytes1 = bytearray(base64.b16decode(self.txt_bytes1))
index = 0
while index < len(readfile):
   index = readfile.find(bytes1, index)
   if index != -1:
      with open("LogFile.txt", "w") as found:
         found.write("found : " + str(index))
         index += 6 # +6 because len(bytes1) == 6

   else:
      break

so i know the starting location of bytes1. now, i want to look for the bytes that come before bytes1, which are 13 F4 18 43 C0 D2. however, in real life situation, those bytes are unkown. the only thing known about those bytes are that they are located before bytes1 and are 6 bytes long. i want to get not the index but the string itself to be then written into a text file. i thought of range() but didn't really know how to use it and it only works with int right? then i saw lookahead and lookbehind but i don't understand the docs. any help will be greatly appreciated.