docs: def dump_addresses(self, network, filename=None):
          """Return a list of address dictionaries for each address in all of the
          accounts in this wallet of the network specified by `network`
          """
          addrs =  [addr.data for a in self.accounts.values() if a.network == network
                              for addr in a.addresses]
          if filename:
              from json import dump
              with open(filename, 'w') as f:
                  dump(addrs, f)
  
          return addrs