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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(template_dict, schema=None):
 """ Is this a valid SAM template dictionary :param dict template_dict: Data to be validated :param dict schema: Optional, dictionary containing JSON Schema representing SAM template :return: Empty string if there are no validation errors in template """


        if not schema:
            schema = SamTemplateValidator._read_schema()

        validation_errors = ""

        try:
            jsonschema.validate(template_dict, schema)
        except ValidationError as ex:
            # Stringifying the exception will give us useful error message
            validation_errors = str(ex)
            # Swallowing expected exception here as our caller is expecting validation errors and
            # not the valiation exception itself
            pass

        return validation_errors