title: Error with avro schema: TypeError: unhashable type: 'dict' Avro Schema
body: <p>An error occurs while processing the schema, I can not understand what the problem is. Where am I making a mistake?</p>
  <p>I have this schema:</p>
  <pre><code>my_schema =
  &quot;&quot;&quot;
      {
          &quot;name&quot;: &quot;MyClass&quot;,
          &quot;type&quot;: &quot;record&quot;,
          &quot;namespace&quot;: &quot;test.namespace&quot;,
          &quot;fields&quot;: [
              {
                  &quot;name&quot;: &quot;id&quot;,
                  &quot;type&quot;: &quot;int&quot;
              },
              {
                  &quot;name&quot;: &quot;data&quot;,
                  &quot;type&quot;: {
                      &quot;name&quot;: &quot;data&quot;,
                      &quot;type&quot;: &quot;record&quot;,
                      &quot;fields&quot;: [
                          {
                              &quot;name&quot;: &quot;detail&quot;,
                              &quot;type&quot;: {
                                  &quot;name&quot;: &quot;detail&quot;,
                                  &quot;type&quot;: &quot;record&quot;,
                                  &quot;fields&quot;: [
                                      {
                                          &quot;name&quot;: &quot;obj_id&quot;,
                                          &quot;type&quot;: &quot;int&quot;
                                      },
                                      {
                                          &quot;name&quot;: &quot;system_id&quot;,
                                          &quot;type&quot;: &quot;int&quot;
                                      }
                                  ]
                              }
                          },
                          {
                              &quot;name&quot;: &quot;email&quot;,
                              &quot;type&quot;: [
                                  &quot;string&quot;,
                                  &quot;null&quot;
                              ]
                          },
                          {
                              &quot;name&quot;: &quot;phone&quot;,
                              &quot;type&quot;: [
                                  &quot;string&quot;,
                                  &quot;null&quot;
                              ]
                          },
                          {
                              &quot;name&quot;: &quot;params&quot;,
                              &quot;type&quot;: {
                                  &quot;type&quot;: &quot;map&quot;,
                                  &quot;values&quot;: &quot;string&quot;
                              }
                          }
                      ]
                  }
              }
          ]
      }
  &quot;&quot;&quot;
  </code></pre>
  <p>This is the data I am using in this scheme::</p>
  <pre><code>value = {
          &quot;id&quot;: 7,
          &quot;data&quot;: {
              &quot;detail&quot;: {
                  &quot;obj_id&quot;: 1,
                  &quot;system_id&quot;: 1
              },
              &quot;email&quot;: &quot;test1@example.com&quot;,
              &quot;phone&quot;: None,
              &quot;params&quot;: {}
          }
      }
  </code></pre>
  <p>Then I initialize AvroProducer:</p>
  <pre><code>value_schema = avro.loads(my_schema)
  producer = AvroProducer(kafka_config, default_value_schema=value_schema)
  producer.produce(topic=topic, value=value)
  </code></pre>
  <p>This is the error I am getting:</p>
  <pre><code>File &quot;/home/Project/test.py&quot;, line 108, in produce
      producer.produce(topic=topic, value=value)
    File &quot;/home/Project/venv/lib/python3.8/site-packages/confluent_kafka/avro/__init__.py&quot;, line 99, in produce
      value = self._serializer.encode_record_with_schema(topic, value_schema, value)
    File &quot;/home/Project/venv/lib/python3.8/site-packages/confluent_kafka/avro/serializer/message_serializer.py&quot;, line 108, in encode_record_with_schema
      schema_id = self.registry_client.register(subject, schema)
    File &quot;/home/Project/venv/lib/python3.8/site-packages/confluent_kafka/avro/cached_schema_registry_client.py&quot;, line 209, in register
      schema_id = schemas_to_id.get(avro_schema, None)
  TypeError: unhashable type: 'dict'
  </code></pre>
  <p>What is causing the error?</p>