How to use the webargs.validate.OneOf function in webargs

def _update_viewarg(self, name, choices):
        ''' Updates the global View arguments validator '''
        viewargs[name] = fields.String(required=True, location='view_args', validate=validate.OneOf(choices))
        # viewargs[name].validate = validate.OneOf(choices)

def _set_params_required(self, subset):
        ''' Set the param validation required parameter '''

        # make list or not
        self._required = [self._required] if not isinstance(self._required, (list, tuple)) else self._required

        # update the required attribute
        for req_param in self._required:
            if req_param in subset.keys():
                subset[req_param].required = True
                subset[req_param].allow_none = False

            if req_param == 'bintemp':
                bintemps = self._get_bin_temps()
                subset[req_param].validate = validate.OneOf(bintemps)
                subset[req_param].validators.append(validate.OneOf(bintemps))

        return subset

add_args = {"x": fields.Float(required=True), "y": fields.Float(required=True)}

    @use_kwargs(add_args)
    def post(self, x, y):
        """An addition endpoint."""
        return {"result": x + y}


class DateAddResource(Resource):

    dateadd_args = {
        "value": fields.Date(required=False),
        "addend": fields.Int(required=True, validate=validate.Range(min=1)),
        "unit": fields.Str(
            missing="days", validate=validate.OneOf(["minutes", "days"])
        ),
    }

    @use_kwargs(dateadd_args)
    def post(self, value, addend, unit):
        """A date adder endpoint."""
        value = value or dt.datetime.utcnow()
        if unit == "minutes":
            delta = dt.timedelta(minutes=addend)
        else:
            delta = dt.timedelta(days=addend)
        result = value + delta
        return {"result": result.isoformat()}


# This error handler is necessary for usage with Flask-RESTful

validate.Regexp('^[0-9-]*$')]),
            'galid': fields.String(required=True, location='view_args', validate=[validate.Length(min=4),
                                   validate.Regexp('^[0-9-]*$')]),
            'bintype': fields.String(required=True, location='view_args'),
            'template': fields.String(required=True, location='view_args'),
            'property_name': fields.String(required=True, location='view_args'),
            'channel': fields.String(required=True, location='view_args'),
            'binid': fields.Integer(required=True, location='view_args', validate=validate.Range(min=-1, max=5800)),
            'plateid': fields.String(required=True, location='view_args', validate=[validate.Length(min=4, max=5),
                                     plate_in_range]),
            'x': fields.Integer(required=True, location='view_args', validate=validate.Range(min=0, max=100)),
            'y': fields.Integer(required=True, location='view_args', validate=validate.Range(min=0, max=100)),
            'mangaid': fields.String(required=True, location='view_args', validate=validate.Length(min=4, max=20)),
            'paramdisplay': fields.String(required=True, location='view_args', validate=validate.OneOf(['all', 'best'])),
            'cube_extension': fields.String(required=True, location='view_args',
                                            validate=validate.OneOf(['flux', 'ivar', 'mask',
                                                                     'disp', 'predisp',
                                                                     'specres', 'specresd',
                                                                     'prespecres',
                                                                     'prespecresd'])),
            'modelcube_extension': fields.String(required=True, location='view_args',
                                                 validate=validate.OneOf(['flux', 'ivar', 'mask',
                                                                          'model', 'emline',
                                                                          'emline_base',
                                                                          'emline_mask'])),
            'colname': fields.String(required=True, location='view_args', allow_none=True),
            'fiberid': fields.Integer(required=True, location='view_args',
                                      validate=validate.Range(min=-1, max=5800)),
            }

# List of all form parameters that are needed in all the API routes
# allow_none = True allows for the parameter to be non-existent when required=False and missing is not set

def _set_params_required(self, subset):
        ''' Set the param validation required parameter '''

        # make list or not
        self._required = [self._required] if not isinstance(self._required, (list, tuple)) else self._required

        # update the required attribute
        for req_param in self._required:
            if req_param in subset.keys():
                subset[req_param].required = True
                subset[req_param].allow_none = False

            if req_param == 'bintemp':
                bintemps = self._get_bin_temps()
                subset[req_param].validate = validate.OneOf(bintemps)
                subset[req_param].validators.append(validate.OneOf(bintemps))

        return subset