[Python] Can anyone explain to me why and how CRC with table optimization works

I couldn't find any good explanation that make me conceptually understand this code of CRC with table optimization, so can anybody please help?

class CRC32Calculator:
def __init__(self):
self.polynomial = 0xEDB88320
self.init_value = 0xFFFFFFFF
self.final_xor = 0xFFFFFFFF
self.table = self._generate_table()

def _generate_table(self):
table = []
for i in range(256):
crc = i
for _ in range(8):
if crc & 1:
crc = (crc >> 1) ^ self.polynomial
else:
crc >>= 1
table.append(crc)
return table

def compute(self, data):
crc = self.init_value
for byte in data:
index = (crc ^ byte) & 0xFF
crc = (crc >> 8) ^ self.table[index]

crc_value = crc ^ self.final_xor
return crc_value.to_bytes(4, byteorder='big')




I know this code is correct, but I can't understand why.

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