syntax_data: {"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"contract_checks:"}]}
source_snippet:     contract_checks: Option<bool> = (None, parse_opt_bool, [TRACKED],
context_before:         "the backend to use"),
context_after:         "emit runtime checks for contract pre- and post-conditions (default: no)"),