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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 _build_url(self, api_call):
 """Build request url. Parameters: api_call (str):
 Base API Call. Returns: Complete url (str). """

        if self.api_version in ('1.13.0', '1.13.0+update.1', '1.13.0+update.2'):
            if '/' not in api_call:
                return "{0}/{1}/index.json".format(self.site_url, api_call)
        return "{0}/{1}.json".format(self.site_url, api_call)