def require_data(self):
files = task.source_missing(self.target)<EOL>if files:<EOL><INDENT>raise DatacatsError('<STR_LIT>' +<EOL>'<STR_LIT:\n>'.join(files))<EOL><DEDENT>if not self.data_exists():<EOL><INDENT>raise DatacatsError('<STR_LIT>'<EOL>'<STR_LIT>')<EOL><DEDENT>if not self.data_complete():<EOL><INDENT>raise DatacatsError('<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>')<EOL><DEDENT>
raise a DatacatsError if the datadir or volumes are missing or damaged