public Builder clearApiVersion() {
      apiVersion_ = getDefaultInstance().getApiVersion();
      bitField0_ = (bitField0_ & ~0x00000040);
      onChanged();
      return this;
    }
<pre>
API version.
</pre>

<code>string api_version = 7;</code>

@return This builder for chaining.
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/OperationMetadata.java