'**DEPRECATED**: Evaluate a JavaScript expression in MongoDB.
:Parameters:
- `code`: string representation of JavaScript code to be
evaluated
- `args` (optional): additional positional arguments are
passed to the `code` being evaluated
.. warning:: the eval command is deprecated in MongoDB 3.0 and
will be removed in a future server version.'

def eval(self, code, *args):

    warnings.warn('Database.eval()    is    deprecated', DeprecationWarning, stacklevel=2)
    if (not isinstance(code, Code)):
        code = Code(code)
    result = self.command('$eval', code, args=args)
    return result.get('retval', None)
