'Lookup a future contract by symbol.
Parameters
symbol : str
The symbol of the desired contract.
Returns
future : Future
The future contract referenced by ``symbol``.
Raises
SymbolNotFound
Raised when no contract named \'symbol\' is found.'

def lookup_future_symbol(self, symbol):

    data = self._select_asset_by_symbol(self.futures_contracts, symbol).execute().fetchone()
    if (not data):
        raise SymbolNotFound(symbol=symbol)
    return self.retrieve_asset(data['sid'])
