def METHOD_NAME(self, stream_name, string):
    fullname = self.full_filename(os.path.basename(stream_name))
    if os.path.exists(fullname):
        print("Stream name already exists")
        return False
    else:
        fd = open(fullname, "wb")
        fd.write(string)
        fd.close()
        self.streams.append(stream_name)
        return True