def transfer_value(from, to, value)
      raise ArgumentError, "value must be greater or equal than zero" unless value >= 0
      delta_balance(from, -value) && delta_balance(to, value)
    end
def transfer_value(from, to, value)
      raise ArgumentError, "value must be greater or equal than zero" unless value >= 0
      delta_balance(from, -value) && delta_balance(to, value)
    end
Transfer a value between two account balance.

 @param from [String] the address of the sending account (binary or hex
   string)
 @param to [String] the address of the receiving account (binary or hex
   string)
 @param value [Integer] the (positive) value to send

 @return [Bool] `true` if successful, otherwise `false`