def flux_bound(self, reaction, direction):
try:<EOL><INDENT>self.maximize({reaction: direction})<EOL><DEDENT>except FluxBalanceError as e:<EOL><INDENT>if not e.result.unbounded:<EOL><INDENT>raise<EOL><DEDENT>return direction * _INF<EOL><DEDENT>else:<EOL><INDENT>return self.get_flux(reaction)<EOL><DEDENT>
Return the flux bound of the reaction.

        Direction must be a positive number to obtain the upper bound or a
        negative number to obtain the lower bound. A value of inf or -inf is
        returned if the problem is unbounded.