def METHOD_NAME() -> kd.sources.Source:
    schema = pa.schema(
        [
            pa.field("time", pa.int32(), nullable=False),
            pa.field("key", pa.int64(), nullable=False),
            pa.field("x", pa.float64()),
            pa.field("y", pa.int32()),
        ]
    )
    return kd.sources.Source(schema, time_column="time", key_column="key")