def __set_bp(self, aProcess):
        """
        Writes a breakpoint instruction at the target address.

        @type  aProcess: L{Process}
        @param aProcess: Process object.
        """
        address = self.get_address()
        self.__previousValue = aProcess.read(address, len(self.bpInstruction))
        if self.__previousValue == self.bpInstruction:
            msg = "Possible overlapping code breakpoints at %s"
            msg = msg % HexDump.address(address)
            warnings.warn(msg, BreakpointWarning)
        aProcess.write(address, self.bpInstruction)
Writes a breakpoint instruction at the target address.

        @type  aProcess: L{Process}
        @param aProcess: Process object.