Empty Extra cause error
if there are no extra properties (i.e. properties that are not part of the default airflow connection properties) an error arises when a None object (or empty string, need to check) is interpreted as json string.
if there are no extra properties (i.e. properties that are not part of the default airflow connection properties) an error arises when a None object (or empty string, need to check) is interpreted as json string.