Fix bug: "is_generate_per_split" should be set to property.

[kngxscn]

is_generate_per_split in TranslateProblem inherits from Text2TextProblem, so it should be set to property. Otherwise when we train model of TranslateProblem, the judgement in

tensor2tensor/tensor2tensor/data_generators/text_problems.py

Line 302 in 65f66e7

if self.is_generate_per_split:

will always be true (self.is_generate_per_split returns a method object), even if we overwrite is_generate_per_split (without @property) to return False in the subclass of TranslateProblem.

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[kngxscn]

I signed it!

[googlebot]

CLAs look good, thanks!

[kyoheikoyama]

Hi, I faced the same error of ImportError: No module named discrete_domains, when I did PR.

Don't you know how to fix it?

[kngxscn]

Hi, I faced the same error of ImportError: No module named discrete_domains, when I did PR.

Don't you know how to fix it?

Sorry, I don't know, and I only see this #1319.

[lukaszkaiser]

Looks good, thanks!

[lukaszkaiser]

Great thanks for correcting this hard-to-see bug that probably affected many people!

[kngxscn]

It's my pleasure!