Function iter_candidate_asset_min_prices 

fn iter_candidate_asset_min_prices<'a, I>(
    activity_keys_for_candidates: I,
    markets_to_price: &HashSet<(CommodityID, RegionID)>,
    existing_prices: &CommodityPrices,
    priced_groups: &HashSet<(CommodityID, RegionID, TimeSliceSelection)>,
    year: u32,
    commodities: &CommodityMap,
    pricing_strategy: &PricingStrategy,
) -> impl Iterator<Item = ((CommodityID, RegionID, TimeSliceSelection), MoneyPerFlow)>
where
    I: Iterator<Item = (&'a AssetRef, &'a TimeSliceID)>,

Calculate prices as the minimum cost across candidate assets, using either a marginal cost or full cost strategy (depending on pricing_strategy). Prices are given for each commodity in the granularity of the commodity’s time slice level. For seasonal/annual commodities, this involves taking a weighted average across time slices for each asset according to potential activity (i.e. the upper activity limit), omitting prices in the extreme case of zero potential activity (Note: this should NOT happen as validation should ensure there is at least one candidate that can provide a price in each time slice for which a price could be required). Costs for candidates are calculated assuming full utilisation.

Arguments

• activity_keys_for_candidates - Iterator over (asset, time slice) tuples for candidate assets
• markets_to_price - Set of (commodity, region) pairs to attempt to price
• existing_prices - Current commodity prices (used to calculate marginal costs)
• priced_groups - Set of (commodity, region, time slice selection) groups that have already been priced using existing assets, so should be skipped when looking at candidates
• year - Year for which prices are being calculated
• commodities - Commodity map
• pricing_strategy - Pricing strategy, either MarginalCost or FullCost

Returns

An iterator of ((commodity, region, time slice selection), price) tuples for the calculated prices. This will include all (commodity, region) combinations in markets_to_price for time slice selections not covered by priced_groups, and for which a price could be determined