Return the data in the buffer as a str of hexadecimal numbers.
sep
An optional single character or byte to separate hex bytes.
bytes_per_sep
How many bytes between separators. Positive values count from
the right, negative values count from the left.
Example:
>>> value = memoryview(b'\xb9\x01\xef')
>>> value.hex()
'b901ef'
>>> value.hex(':')
'b9:01:ef'
>>> value.hex(':', 2)
'b9:01ef'
>>> value.hex(':', -2)
'b901:ef'
3.8: Similar to bytes.hex(), memoryview.hex() now supports optional sep and bytes_per_sep parameters to insert separators between bytes in the hex output.