def augment_cycle(self, amount, cycle):
        '''
        API:
            augment_cycle(self, amount, cycle):
        Description:
            Augments 'amount' unit of flow along cycle.
        Pre:
            Arcs should have 'flow' attribute.
        Inputs:
            amount: An integer representing the amount to augment
            cycle: A list representing a cycle
        Post:
            Changes 'flow' attributes of arcs.
        '''
        index = 0
        k = len(cycle)
        while index<(k-1):
            i = cycle[index]
            j = cycle[index+1]
            if (i,j) in self.edge_attr:
                flow_ij = self.edge_attr[(i,j)]['flow']
                self.edge_attr[(i,j)]['flow'] = flow_ij+amount
            else:
                flow_ji = self.edge_attr[(j,i)]['flow']
                self.edge_attr[(j,i)]['flow'] = flow_ji-amount
            index += 1
        i = cycle[k-1]
        j = cycle[0]
        if (i,j) in self.edge_attr:
            flow_ij = self.edge_attr[(i,j)]['flow']
            self.edge_attr[(i,j)]['flow'] = flow_ij+amount
        else:
            flow_ji = self.edge_attr[(j,i)]['flow']
            self.edge_attr[(j,i)]['flow'] = flow_ji-amount
def augment_cycle ( self , amount , cycle ) : index = 0 k = len ( cycle ) while index < ( k - 1 ) : i = cycle [ index ] j = cycle [ index + 1 ] if ( i , j ) in self . edge_attr : flow_ij = self . edge_attr [ ( i , j ) ] [ 'flow' ] self . edge_attr [ ( i , j ) ] [ 'flow' ] = flow_ij + amount else : flow_ji = self . edge_attr [ ( j , i ) ] [ 'flow' ] self . edge_attr [ ( j , i ) ] [ 'flow' ] = flow_ji - amount index += 1 i = cycle [ k - 1 ] j = cycle [ 0 ] if ( i , j ) in self . edge_attr : flow_ij = self . edge_attr [ ( i , j ) ] [ 'flow' ] self . edge_attr [ ( i , j ) ] [ 'flow' ] = flow_ij + amount else : flow_ji = self . edge_attr [ ( j , i ) ] [ 'flow' ] self . edge_attr [ ( j , i ) ] [ 'flow' ] = flow_ji - amount
API:
            augment_cycle(self, amount, cycle):
        Description:
            Augments 'amount' unit of flow along cycle.
        Pre:
            Arcs should have 'flow' attribute.
        Inputs:
            amount: An integer representing the amount to augment
            cycle: A list representing a cycle
        Post:
            Changes 'flow' attributes of arcs.