def parse_int(self, buff, start, end):
<INDENT>num = self.parse_uint(buff, start, end)<EOL>l = (end - start)<EOL>return self.twos_comp(num, l * <NUM_LIT:8>)<EOL><DEDENT>return struct.unpack_from(self.structmap[end - start], buff, start)[<NUM_LIT:0>]<EOL>
parse an integer from the buffer given the interval of bytes
:param buff:
:param start:
:param end: