def includes_negative?(id, bnf = nil)
      raise 'The txn ID has to be of type Integer' unless id.is_a?(Integer)
      !txns.find { |t| t.id == id && (bnf.nil? || t.bnf == bnf) && t.amount.negative? }.nil?
    end
def includes_negative?(id, bnf = nil)
      raise 'The txn ID has to be of type Integer' unless id.is_a?(Integer)
      !txns.find { |t| t.id == id && (bnf.nil? || t.bnf == bnf) && t.amount.negative? }.nil?
    end
def includes_negative? ( id , bnf = nil ) raise 'The txn ID has to be of type Integer' unless id . is_a? ( Integer ) ! txns . find { | t | t . id == id && ( bnf . nil? || t . bnf == bnf ) && t . amount . negative? } . nil? end
Returns TRUE if the wallet contains a payment sent with the specified
 ID, which was sent to the specified beneficiary.
Returns TRUE if the wallet contains a payment sent with the specified ID which was sent to the specified beneficiary .