/// Whether an installation may retain unrelated packages.
#[derive(Debug, Clone, Copy)]
pub enum Modifications {
/// Use `pip install` semantics, whereby existing installations are left as-is, unless they are
/// marked for re-installation or upgrade.
///
/// Ensures that the resulting environment is sufficient to meet the requirements, but without
/// any unnecessary changes.
Sufficient,
/// Use `pip sync` semantics, whereby any existing, extraneous installations are removed.
///
/// Ensures that the resulting environment is an exact match for the requirements, but may
/// result in more changes than necessary.
Exact,
}