Fixed pep8 errors "F405" in converter

[tfujiwar]

What this patch does to fix the issue.

Many pep8 errors occurred because of star imports.
This PR reduces pep8 errors in converter from 432 to 96.

F405 'List' may be undefined, or defined from star imports: .data_types

Link to any relevant issues or pull requests.

#979

[bo-code-review-bot]

This PR needs Approvals as follows.

• Ownership Approval for / from iizukak, tkng, ruimashita

Please choose reviewers and requet reviews!

Click to see how to approve each reviews

You can approve this PR by triggered comments as follows.

• Approve all reviews requested to you (readability and ownership) and LGTM review
  Approval, LGTM

• Approve all ownership reviews
  Ownership Approval or OA

• Approve all readability reviews
  Readability Approval or RA

• Approve specified review targets

  • Example of Ownership Reviewer of /: Ownership Approval for / or OA for /
  • Example of Readability Reviewer of Python: Readability Approval for Python or RA for Python

• Approve LGTM review
  LGTM

See all trigger comments

Please replace [Target] to review target

• Ownership Approval
  • Ownership Approval for [Target]
  • OA for [Target]
  • Ownership Approval
  • OA
  • Approval
• Readability Approval
  • Readability Approval for [Target]
  • RA for [Target]
  • [Target] Readability Approval
  • [Target] RA
  • Readability Approval
  • RA
  • Approval
• LGTM
  • LGTM
  • lgtm

[iizukak]

OA

[tfujiwar]

/ready

[bo-mergebot]

⏳Merge job is queued...