public function putAttachment(string $key, string $value): MeasurementInterface
    {
        $this->attachments[$key] = $value;
        return $this;
    }
public function putAttachment(string $key, string $value): MeasurementInterface
    {
        $this->attachments[$key] = $value;
        return $this;
    }
public function putAttachment ( string $ key , string $ value ) : MeasurementInterface { $ this -> attachments [ $ key ] = $ value ; return $ this ; }
Add an Exemplar Attachment to our map. If the key already exists, the
existing Attachment in the map will be overriden with the new value.

@param string $key The Attachment key.
@param string $value The Attachment value.
@return MeasurementInterface
Add an Exemplar Attachment to our map . If the key already exists the existing Attachment in the map will be overriden with the new value .