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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def validate(self, value):
 """ Validates that the input is a list or tuple. """

        if self.required and not value:
            raise OAuthValidationError({'error': 'invalid_request'})

        # Validate that each value in the value list is in self.choices.
        for val in value:
            if not self.valid_value(val):
                raise OAuthValidationError({
                    'error': 'invalid_request',
                    'error_description': _("'%s' is not a valid scope.") % \
                            val})