add mtl training code

[haofengac]

No description provided.

[lgtm-com]

This pull request introduces 102 alerts when merging 96a563c into 499ef01 - view on LGTM.com

new alerts:

• 27 for Unused local variable
• 27 for Unused import
• 23 for Signature mismatch in overriding method
• 10 for Wrong name for an argument in a class instantiation
• 5 for Except block handles 'BaseException'
• 2 for First argument to super() is not enclosing class
• 1 for Non-callable called
• 1 for Unreachable code
• 1 for 'import *' may pollute namespace
• 1 for Suspicious unused loop iteration variable
• 1 for Module is imported with 'import' and 'import from'
• 1 for Variable defined multiple times
• 1 for Redundant assignment
• 1 for Nested loops with same variable