unrecognised option '--ast'

[HosseinAsadi]

Hi
after run this command
solidity_flattener contracts/MyNFT.sol

---

unrecognised option '--ast'
Traceback (most recent call last):
File "/usr/local/bin/solidity_flattener", line 4, in
flattener.core.main()
File "/usr/local/lib/python3.9/site-packages/flattener/core.py", line 97, in main
solc_proc.check_returncode()
File "/usr/local/Cellar/[email protected]/3.9.9/Frameworks/Python.framework/Versions/3.9/lib/python3.9/subprocess.py", line 460, in check_returncode
raise CalledProcessError(self.returncode, self.args, self.stdout,
subprocess.CalledProcessError: Command '['solc', '--ast', 'contracts/MyNFT.sol']' returned non-zero exit status 1.