code: function getMissingColumnCheck(expectedHeader, caseSensitive, severity) {
  
  	return function (content) {
  		let actualHeader;
  		if (caseSensitive) {
  			actualHeader = content;
  		} else {
  			actualHeader = arrayToUpperCase(content);
  			expectedHeader = arrayToUpperCase(expectedHeader);
  		}
  
  		// the header must have all the expected columns but may have more
  		let err = _missingColumns(expectedHeader, actualHeader);
  		if (err) {
  			return {
  				errorCode: 'CHECK_HEADER_MISSING_COLUMNS',
  				severity: severity,
  				message: 'The following columns are missing in the header: [' + err.join() + ']'
  			};
  		}
  	};
  }
docs: Creates the missing column check
  @param expectedHeader The expected header
  @param caseSensitive Is the header case sensitive
  @param severity The severity if the check fails