ID 500199 - AttributeError when method chaining delete() and build() on a GroupBuilder object

Problem summary
AttributeError when method chaining delete() and build() on a GroupBuilder object.

Customer reported version
katana.n_a

Customer reported platform

Steps to reproduce

1) In the Python tab, run:

FnAttribute.GroupBuilder().delete("").build()

Expected behavior
No error.

Actual behavior

File "<string>", line 1, in <module>
AttributeError: 'NoneType' object has no attribute 'build'

Workaround
Separate the GroupBuilder calls:

gb = FnAttribute.GroupBuilder()
gb.delete("")
gb.build()

Reproduced by support
This bug has been reproduced in:
Katana 5.0v1 - CentOS 7, Windows 10
Katana 4.5v1 - CentOS 7 Windows 10

Unable to reproduce bug in:
Katana 4.0v5 - CentOS 7, Windows 10

Earliest version tested
Katana 4.0v5 - This issue doesn't appear in this version and has regressed