Graph with gaps (NaNs) causing Error

[Vasco-Da-Gama-png]

When you have a graph with gaps in it and labellines tries to label the line in the gap, this causes the following error:
ValueError: x label location is outside data range!

Here is a photo of an example plot:

[scottshambaugh]

I can reproduce with this script:

import matplotlib.pyplot as plt
import numpy as np
from labellines import labelLines

x = np.linspace(0, 10, 100)
x[10:30] = np.nan

fig, ax = plt.subplots()

for i in range(10):
    y = np.sin(x + i)
    ax.plot(x, y, label=f'y={i}')

labelLines(ax.get_lines(), zorder=2.5)

plt.show(block=True)

@Vasco-Da-Gama-png it looks like you're using a datetime axis, once #210 is merged in you'll be able to work around this by manually setting label locations with the xvals argument.

[cphyc]

Closed by #211 and #212.