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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 _fields_common(self):
 """Returns a dictionary of fields and values that are common to all events for which fields dictionaries are created. """

        result = {}
        if not self.testmode:
            result["__reponame__"] = self.repo.repo.full_name
            result["__repodesc__"] = self.repo.repo.description
            result["__repourl__"] = self.repo.repo.html_url
            result["__repodir__"] = self.repodir

            if self.organization is not None:
                owner = self.repo.organization
            else:
                owner = self.repo.user
                
            result["__username__"] = owner.name
            result["__userurl__"] = owner.html_url
            result["__useravatar__"] = owner.avatar_url
            result["__useremail__"] = owner.email

        return result