Error in Dirac Bracket Calculation for Wikipedia?
I am reading a Wikipedia article on Dirac brackets. At the bottom of the page "illustration on example provided" the article states that for a system with constraints: $$ \phi_1 = p_x + \frac{qB}{2c}y \approx 0 \Longrightarrow p_x = -\frac{qB}{2c}y, $$ $$ \phi_2 = p_y - \frac{qB}{2c}x \approx 0 \Longrightarrow p_y = \frac{qB}{2c}x. $$
The Dirac bracket is given by: $$ {f, g}{DB} = {f, g}{PB} + \frac{c}{qB}{f, \phi_1}{PB} {\phi_2, g}{PB} - \frac{c}{qB}{f, \phi_2}{PB} {\phi_1, g}{PB} . $$
The article then states that $$ {p_x, p_y}_{DB} = - \frac{qB}{4c}. 394