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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 approve(self, sha=None, **kwargs):
 """Approve the merge request. Args: sha (str):
 Head SHA of MR **kwargs: Extra options to send to the server (e.g. sudo) Raises: GitlabAuthenticationError: If authentication is not correct GitlabMRApprovalError: If the approval failed """

        path = '%s/%s/approve' % (self.manager.path, self.get_id())
        data = {}
        if sha:
            data['sha'] = sha

        server_data = self.manager.gitlab.http_post(path, post_data=data,
                                                    **kwargs)
        self._update_attrs(server_data)