title: Geodjango django.contrib.gis.geos Linestring to Shapely Linestring
body: <p>I know its a basic problem, but I just got started with GIS and I'm badly stuck.</p>
  <p>I tried to use a  <code>django.contrib.gis.geos import LineString</code> Linestring with a shapely function <code>shapely.ops.snap()</code>. Obviously its missing the attribute of the shapely object and I get a <code>AttributeError: 'LineString' object has no attribute '_geom'</code></p>
  <p>How do I turn the LineString into a shapely LineString and back into a geodjango geos LineString to save it to the database?</p>
  <p>It seems a bit weird as well as the docs say its both a GEOS geometry and interchangable(<a href="https://code.djangoproject.com/wiki/GEOSGeometry" rel="nofollow noreferrer">https://code.djangoproject.com/wiki/GEOSGeometry</a>) but it seems it is not.</p>
  <p>Feeling bad to ask this but I'm not finding the appropriate function and the docs seem a bit more minimalistic than what I'm used to (even though the libraries seem great) :(</p>