handles string as package name

[pyther-hub]

solved the issue #1638 by simply converting the string to list element rdt.display_all_rdataset_names("aer") the above command works same as rdt.display_all_rdataset_names(["aer"])

as now the code converts the string back to a list with one element its a simple way to solve this

as you con see in the screenshots the output is same