def _check_input(self, input):
        """Checks the validity of the input.

        In case of an invalid input throws ValueError.
        """
        if isinstance(input, str):
            return 'st'
        elif isinstance(input, list):
            if all(isinstance(item, str) for item in input):
                return 'gst'

        raise ValueError("String argument should be of type String or"
                                     " a list of strings")
def _check_input(self, input):
        """Checks the validity of the input.

        In case of an invalid input throws ValueError.
        """
        if isinstance(input, str):
            return 'st'
        elif isinstance(input, list):
            if all(isinstance(item, str) for item in input):
                return 'gst'

        raise ValueError("String argument should be of type String or"
                                     " a list of strings")
def _check_input ( self , input ) : if isinstance ( input , str ) : return 'st' elif isinstance ( input , list ) : if all ( isinstance ( item , str ) for item in input ) : return 'gst' raise ValueError ( "String argument should be of type String or" " a list of strings" )
Checks the validity of the input.

        In case of an invalid input throws ValueError.
Checks the validity of the input .