Converts data string to iterable.

        Parameters:
        -----------
        datastring: string, defaults to None
        \tThe data string to be converted.
        \tself.get_clipboard() is called if set to None
        sep: string
        \tSeparator for columns in datastring

def _convert_clipboard(self, datastring=None, sep='\t'):
        """Converts data string to iterable.

        Parameters:
        -----------
        datastring: string, defaults to None
        \tThe data string to be converted.
        \tself.get_clipboard() is called if set to None
        sep: string
        \tSeparator for columns in datastring

        """

        if datastring is None:
            datastring = self.get_clipboard()

        data_it = ((ele for ele in line.split(sep))
                            for line in datastring.splitlines())
        return data_it