docs: def get(self, name, default=None):
          """Get value."""
          default = default if default is not None else self.default
          try:
              value = getattr(_settings, name)
          except AttributeError:
              value = os.environ.get(name, default) if self.from_env else default
              # Convert env variable.
              if value != default:
                  value = self.env_clean(value)
  
          return self.validate(name, value)