Common unit IDs for block model attributes.

These are the most commonly used unit IDs. For a complete list, use get_available_units() to query the Block Model Service.

Example usage: from evo.blockmodels.typed import Units

# Create block model with units
bm_data = RegularBlockModelData(
    ...
    units={
        "grade": Units.GRAMS_PER_TONNE,
        "density": Units.TONNES_PER_CUBIC_METRE,
    },
)

# Add attribute with unit
await bm_ref.add_attribute(df, "metal_content", unit=Units.KILOS_PER_CUBIC_METRE)