def flux_expr(self, reaction):
        """Get LP expression representing the reaction flux."""
        if isinstance(reaction, dict):
            return self._v.expr(iteritems(reaction))
        return self._v(reaction)
def flux_expr ( self , reaction ) : if isinstance ( reaction , dict ) : return self . _v . expr ( iteritems ( reaction ) ) return self . _v ( reaction )
Get LP expression representing the reaction flux.