@property<EOL><INDENT>def request_pdu(self):<DEDENT>
if None in [self.starting_address, self.quantity]:<EOL><INDENT>raise Exception<EOL><DEDENT>return struct.pack('<STR_LIT>', self.function_code, self.starting_address,<EOL>self.quantity)<EOL>
Build request PDU to read coils.

        :return: Byte array of 5 bytes with PDU.