Kernel died(code: 1). AttributeError: type object 'IOLoop' has no attribute “initialized“ Problem solution

Problem Description

When jupyter runs a certain project, all the dependent packages are installed, but it cannot run, and Kernel died(code: 1). AttributeError: type object 'IOLoop' has no attribute “initialized” will pop up.

problem solved

This problem occurs because the version of tornado is too high and needs to be adjusted to 4.5.
At the same time, it should be noted that some computers may have multiple python environments. It is necessary to clarify which environment the current project is in, and then adjust the version.

1. conda View all environments
   conda env list
   My environment has the following two, among which the environment where the project is located is PDE-Net
   
2. Enter the environment that needs to adjust the version
   conda active PDE-Net
   
3. Uninstall tornado in the current environment
   pip uninstall tornado
   
4. After the uninstallation is complete, reinstall tornado
   pip install tornado==4.4.3
   
   to solve the problem~