'Create an instance of a :class:`~.TransactionLink`.
Note:
In an IPLD implementation, this class is not necessary anymore,
as an IPLD link can simply point to an object, as well as an
objects properties. So instead of having a (de)serializable
class, we can have a simple IPLD link of the form:
`/<tx_id>/transaction/outputs/<output>/`.
Args:
txid (str, optional): A Transaction to link to.
output (int, optional): An Outputs\'s index in a Transaction with
id `txid`.'

def __init__(self, txid=None, output=None):

    self.txid = txid
    self.output = output
