def quotation(self, origin, target):
        """Return quotation between two currencies (origin, target)"""
        if not self._backend:
            raise ExchangeBackendNotInstalled()
        return self._backend.quotation(origin, target)
def quotation ( self , origin , target ) : if not self . _backend : raise ExchangeBackendNotInstalled ( ) return self . _backend . quotation ( origin , target )
Return quotation between two currencies (origin, target)