def METHOD_NAME(self) -> Optional[int]:
    """Get ID of the variable used in map tab."""
    id_ = None
    if "map" in self.config:
        if "variableId" in self.config["map"]:
            id_ = self.config["map"]["variableId"]
        elif len(self.config["dimensions"]) == 1:
            id_ = self.config["dimensions"][0]["variableId"]
    return id_