'The plot interval for the default geometric plot of the Segment gives
values that will produce the full segment in a plot.
Parameters
parameter : str, optional
Default value is \'t\'.
Returns
plot_interval : list
[parameter, lower_bound, upper_bound]
Examples
>>> from sympy import Point, Segment
>>> p1, p2 = Point(0, 0), Point(5, 3)
>>> s1 = Segment(p1, p2)
>>> s1.plot_interval()
[t, 0, 1]'

def plot_interval(self, parameter='t'):

    t = _symbol(parameter)
    return [t, 0, 1]
