Initializing with 0 in case we don 't have left or right boundary
lb = 0 NEW_LINE rb = 0 NEW_LINE if ( t . left != None ) : NEW_LINE INDENT lb = uncoveredSumLeft ( t . left ) NEW_LINE DEDENT if ( t . right != None ) : NEW_LINE INDENT rb = uncoveredSumRight ( t . right ) NEW_LINE DEDENT