def get_by_id(id)
      accts = @accounts.select {|acct| acct.uuid == id }

      if accts.size == 0
        raise KeyError, "account with id #{id} unknown"
      elsif accts.size > 1
        logger.warn "multiple accounts with same UUID found", uuid: id
      end

      accts[0]
    end
def get_by_id(id)
      accts = @accounts.select {|acct| acct.uuid == id }

      if accts.size == 0
        raise KeyError, "account with id #{id} unknown"
      elsif accts.size > 1
        logger.warn "multiple accounts with same UUID found", uuid: id
      end

      accts[0]
    end
Return the account with a given id.

 Note that accounts are not required to have an id.

 @raise [KeyError] if no matching account can be found