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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 site(self, site):
 """ Sets the site of this OauthTokenReference. :param site: The site of this OauthTokenReference. :type: str """

        if site is None:
            raise ValueError("Invalid value for `site`, must not be `None`")
        if site is not None and len(site) > 255:
            raise ValueError("Invalid value for `site`, length must be less than or equal to `255`")
        if site is not None and len(site) < 3:
            raise ValueError("Invalid value for `site`, length must be greater than or equal to `3`")
        if site is not None and not re.search('(?:[a-z](?:[-a-z0-9]{0,61}[a-z0-9])?\\.)+[a-z]{2,}(?:@[a-z0-9](?:[-.](?=[a-z0-9])|[a-z0-9]){0,29})?', site):
            raise ValueError("Invalid value for `site`, must be a follow pattern or equal to `/(?:[a-z](?:[-a-z0-9]{0,61}[a-z0-9])?\\.)+[a-z]{2,}(?:@[a-z0-9](?:[-.](?=[a-z0-9])|[a-z0-9]){0,29})?/`")

        self._site = site