@property<EOL><INDENT>def num_fails(self):<DEDENT>
n = len(self.failed_phase_list)<EOL>if self.phase_stack[-<NUM_LIT:1>].status in (SolverStatus.failed, SolverStatus.cyclic):<EOL><INDENT>n += <NUM_LIT:1><EOL><DEDENT>return n<EOL>
Return the number of failed solve steps that have been executed.
        Note that num_solves is inclusive of failures.