after_mint
Extendable function that allows the developer to add more functionality to the mint function, after the mint happens.
This allows, for example, to check that any given condition is present after the tokens have been minted.
If this function throws an exception, the asset will not be minted.
Throws if any extension of this function throws.
Parameters
account
the account that has received the newly minted tokens
asset
the asset that has been minted
amount
the amount of tokens that have been minted