fix pep8

notebooks/cross_instrument/background_estimation_imaging/Imaging_Sky_Background_Estimation.ipynb

@@ -56,17 +56,15 @@
     "                                 Tophat2DKernel, convolve)\n",
     "from astropy.modeling import fitting, models\n",
     "from astropy.nddata.blocks import block_reduce\n",
-    "from astropy.stats import SigmaClip, gaussian_fwhm_to_sigma\n",
+    "from astropy.stats import SigmaClip\n",
     "from astropy.table import Table\n",
     "from IPython.display import Image\n",
     "from jdaviz import Imviz\n",
-    "from photutils.background import (Background2D, BiweightLocationBackground,\n",
+    "from photutils.background import (Background2D,\n",
     "                                  BkgIDWInterpolator, BkgZoomInterpolator,\n",
-    "                                  MedianBackground, SExtractorBackground)\n",
+    "                                  MedianBackground)\n",
     "from photutils.datasets import make_gaussian_sources_image\n",
     "from photutils.segmentation import detect_sources, make_2dgaussian_kernel\n",
-    "from photutils.utils import ShepardIDWInterpolator as idw\n",
-    "from scipy import interpolate, ndimage, stats\n",
     "from scipy.ndimage import median_filter"
    ]
   },
@@ -1221,7 +1219,7 @@
    "source": [
     "plt.figure(figsize=(10, 6))\n",
     "perfect = rms['perfect']\n",
-    "plt.plot(rms['widths'], rms['bkg1']/perfect, alpha=0.5,label='bkg1')\n",
+    "plt.plot(rms['widths'], rms['bkg1']/perfect, alpha=0.5, label='bkg1')\n",
     "plt.plot(rms['widths'], rms['bkg2']/perfect, alpha=0.5, label='bkg2')\n",
     "plt.plot(rms['widths'], rms['bkg3']/perfect, alpha=0.5, label='bkg3')\n",
     "plt.plot(rms['widths'], rms['bkg4']/perfect, alpha=0.5, label='bkg4')\n",