def _send(self, cmd: str):
logger.debug('<STR_LIT>', cmd)<EOL>try:<EOL><INDENT>self._proc.stdout.flush()<EOL>self._proc.stdin.write(f'<STR_LIT>')<EOL><DEDENT>except IOError as e:<EOL><INDENT>raise SolverError(str(e))<EOL><DEDENT>
Send a string to the solver.

:param cmd: a SMTLIBv2 command (ex. (check-sat))