When installing with pip, pip install sqlalchemy all is ok.

When installing with poetry I am getting the error

➜  backend poetry add sqlalchemy
Using version ^1.4.23 for SQLAlchemy

Updating dependencies
Resolving dependencies... (0.1s)

  AttributeError

  'EmptyConstraint' object has no attribute 'allows'

  at ~/.poetry/lib/poetry/_vendor/py3.8/poetry/core/version/markers.py:291 in validate
      287│
      288│         if self._name not in environment:
      289│             return True
      290│
    → 291│         return self._constraint.allows(self._parser(environment[self._name]))
      292│
      293│     def without_extras(self):  # type: () -> MarkerTypes
      294│         return self.exclude("extra")
      295│
➜  backend

Try poetry self update, then poetry update.