@staticmethod
def _boolean_list_to_string(l):
    """
        Converts a boolean list to a string of T and F characters.

        Parameters
        ----------

        l : boolean list
            Boolean list to convert.

        Returns
        -------

        str
           string of T and F characters representing the content of the boolean list.
        """
    res = ''
    for x in l:
        if x:
            res += 'T '
        else:
            res += 'F '
    return res
