@property<EOL><INDENT>def failed(self):<DEDENT>
<EOL>if not self.section_to_status_by_command:<EOL><INDENT>raise ValueError("<STR_LIT>")<EOL><DEDENT>return <NUM_LIT:0> == len(self.failures)<EOL>
Determine whether *every* command succeeded for *every* config file
section that was validated during instance construction.

:return bool: conjunction of execution success test result values,
    obtained by testing each executable in every validated section