This function performs checks on the column names of a Validator object to ensure they follow specific naming conventions and
meet schema conditions.
check_colnames(validator)The updated Validator object with QA entries for each check.
A Validator object containing the column names to be checked.
The function performs the following checks on the column names:
Ensures column names do not contain spaces.
Ensures column names do not contain symbols other than underscores.
Ensures column names do not contain uppercase letters.
For each check, a QA entry is added to the Validator object with details about the check, whether it passed, and the IDs of failing columns (if any). # nolint: line_length_linter.