René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"contour ignores `lw` argument, no warning/error","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\nThe command `contour` does not use `lw` arguments (unlike, e.g., `plot`), and does not report an error or warning.  The `linewidths` argument works fine.  A simple fix is to explicitly look for `lw` arguments and set `linewidths` to that.  Happy to put in a PR for this, but I wanted to check first.\r\n\r\n```python\r\nimport numpy as np\r\nimport matplotlib as mpl\r\nimport matplotlib.pyplot as plt\r\nprint(mpl.__version__)\r\n\r\nfig, axes = plt.subplots(ncols=3)\r\n\r\nfor ax, lw, arg in zip(axes, [1.0, 4.0, 4.0], ['lw', 'lw', 'linewidths']):\r\n    aa = np.random.normal(size=1000)\r\n    bb = np.random.normal(size=aa.size)\r\n    hist, xe, ye = np.histogram2d(aa, bb)\r\n    kw = {arg: lw}\r\n    ax.contour(hist, **kw)\r\n    ax.set_title('{}: {}'.format(arg, lw))\r\n\r\nplt.show()\r\n```\r\n\r\n**Actual outcome**\r\n\r\n![mpl](https://user-images.githubusercontent.com/3839265/55428241-4c742180-554e-11e9-8594-4d7d85a4273a.png)\r\n\r\n\r\n**Matplotlib version**\r\n  * Matplotlib version: 3.0.2\r\n","author":{"url":"https://github.com/lzkelley","@type":"Person","name":"lzkelley"},"datePublished":"2019-04-02T18:50:46.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":8},"url":"https://github.com/13848/matplotlib/issues/13848"}