get_all_children(search_key, child_type, columns=[])
Get all children of a particular child type of an sobject
ticket - authentication ticket
search_key - a unique identifier key representing an sobject
child_type - the search_type of the children to search for
filters - extra filters on the query : see query method for examples
columns - list of column names to be included in the returned dictionary
list of dictionary - a list of sobjects dictionaries