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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 my_permissions(self, projectKey=None, projectId=None, issueKey=None, issueId=None, ):
 """Get a dict of all available permissions on the server. :param projectKey: limit returned permissions to the specified project :type projectKey: Optional[str] :param projectId: limit returned permissions to the specified project :type projectId: Optional[str] :param issueKey: limit returned permissions to the specified issue :type issueKey: Optional[str] :param issueId: limit returned permissions to the specified issue :type issueId: Optional[str] :rtype: Dict[str, Dict[str, Dict[str, str]]] """

        params = {}
        if projectKey is not None:
            params['projectKey'] = projectKey
        if projectId is not None:
            params['projectId'] = projectId
        if issueKey is not None:
            params['issueKey'] = issueKey
        if issueId is not None:
            params['issueId'] = issueId
        return self._get_json('mypermissions', params=params)