title: Can't figure out serialization error in Elasticsearch Python API
body: <p>My code is displayed below. </p>
  
  <pre><code>client = Elasticsearch(url, http_auth = (username, password), verify_certs = False, read_timeout=50, terminate_after=25000)
  
  examplename = 'GEOS.fp.asm.inst1_2d_smp_Nx.20180508_1700.V01.nc4'
  
  s = Search(using = client, index = [set_index]).source(['metadata.Filename'])\
  .query('match', Filename={examplename})
  
  
  total = s.count()
  </code></pre>
  
  <p>The error message is: </p>
  
  <pre><code>elasticsearch.exceptions.SerializationError: ({'query': {'match': {'Filename': set(['GEOS.fp.asm.inst1_2d_smp_Nx.20180508_1700.V01.nc4'])}}}, TypeError("Unable to serialize set(['GEOS.fp.asm.inst1_2d_smp_Nx.20180508_1700.V01.nc4']) (type: &lt;type 'set'&gt;)",))
  </code></pre>
  
  <p>In general, I don't need my search term to match the whole document. So for example if the document is named GEOS.fp.asm.inst1_2d_smp_Nx.20180508_1700.V01.nc4, I want that document to be returned if I query for 20180508. </p>