Validate that input variables match the placeholders in a format string.
Checks that the provided input variables can be used to format the given string without missing or extra keys. This is useful for validating prompt templates before runtime.
Example:
fmt = StrictFormatter() fmt.validate_input_variables("Hello, {name}!", ["name"]) # OK fmt.validate_input_variables("Hello, {name}!", ["other"]) # Raises
