def add_record_check(self, record_check, modulus=<NUM_LIT:1>):
assert callable(record_check), '<STR_LIT>'<EOL>t = record_check, modulus<EOL>self._record_checks.append(t)<EOL>
Add a record check function.

Arguments
---------

`record_check` - a function that accepts a single argument (a record as
a dictionary of values indexed by field name) and raises a
`RecordError` if the record is not valid

`modulus` - apply the check to every nth record, defaults to 1 (check
every record)