Fix saving failed when the strategy is 'better'

[WenjieDu]

What does this PR do?

1. fixing Model saving bug #464;

Before submitting

• Was this discussed/approved via a GitHub issue? Please add a link to it if that's the case.
• I have commented my code, particularly in hard-to-understand areas.
• I have written necessary tests and already run them locally.

[coveralls]

Pull Request Test Coverage Report for Build 10025647409

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 84.035%

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Totals
Change from base Build 10020935521:	0.0%
Covered Lines:	10580
Relevant Lines:	12590

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💛 - Coveralls