def pybool(v_str, strict_logical=True):
    """Convert string repr of Fortran logical to Python logical."""
    assert isinstance(v_str, str)
    assert isinstance(strict_logical, bool)
    if strict_logical:
        v_bool = v_str.lower()
    else:
        try:
            if v_str.startswith('.'):
                v_bool = v_str[1].lower()
            else:
                v_bool = v_str[0].lower()
        except IndexError:
            raise ValueError('{0} is not a valid logical constant.'.format(
                v_str))
    if v_bool in ('.true.', '.t.', 'true', 't'):
        return True
    elif v_bool in ('.false.', '.f.', 'false', 'f'):
        return False
    else:
        raise ValueError('{0} is not a valid logical constant.'.format(v_str))
