I want to label my vertical lines with matplotlib's .vline command, but for some reason the label parameter doesn't do anything/show anything on the final plot. Does anyone know how to get the label to show?

```
plt.vlines(x=pah, ymin=0, ymax=0.6, colors='0.75', linestyles='dashed', label='PAHs')

```

Everything works apart from the label.

Many thanks,

L