def _nob_print_params(tab_length=2, line_length=40):
    """Defining parameters and special characters
       for nested object printing
    Inputs:
    ----------
    tab_length : Number of spaces describing a tab
    line_length : the maximum allowed number of characters in a line

    Returns :
    ---------
    chars : a dictionnary gathering special characters and max line length
    """
    chars = dict()
    chars['vertical_bar'] = u'┃'
    chars['horizontal_bar'] = u'━'
    chars['child_bar'] = u'┓'
    chars['standard_child'] = u'┣'
    chars['last_child'] = u'┗'
    chars['tab'] = ' ' * tab_length
    chars['max_length'] = line_length
    return chars
