def parse_bibs_data(bibs)
      bibs.reduce(Hash.new) { |acc, bib|
        acc.merge({"#{bib.id}" => {holdings: build_holdings_for(bib)}})
      }
    end
def parse_bibs_data(bibs)
      bibs.reduce(Hash.new) { |acc, bib|
        acc.merge({"#{bib.id}" => {holdings: build_holdings_for(bib)}})
      }
    end
Data structure for holdings information of bib records.
 A hash with mms ids as keys, with values of an array of
 one or more hashes of holdings info