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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 is_suitable(self, request):
 """ Checks if key is suitable for given request according to key type and request's user agent. """

        if self.key_type:
            validation = KEY_TYPE_VALIDATIONS.get( self.get_type() )
            return validation( request ) if validation else None
        return True