How to Fix the Bokeh Version Error in PyCharm and Upgrade Seamlessly

Introduction

When using Python for plotting, many start with matplotlib, but for more advanced graphics libraries like Bokeh are often used. This article focuses on a common Bokeh runtime error and how to resolve it.

Typical Error

Running a Bokeh script may raise an error such as:

raise ValueError("expected an element of either %s, got %r" % (nice_join(self.type_params), value))
ValueError: expected an element of either List(String) or List(Int), got …

The error usually appears as shown in the screenshot.

Root Cause

The error is caused by using an outdated Bokeh version (below 0.13.0). Newer versions have fixed the issue.

Solution: Upgrade Bokeh in PyCharm

Open PyCharm Settings.

Navigate to Project Interpreter and locate the Bokeh package.

Click the upgrade arrow icon to install the latest version.

Wait for the installation to finish; the version number will update.

Result

After upgrading, the script runs without the previous error, and the Bokeh plot renders correctly.

Conclusion

This guide demonstrated one of the most frequent Bokeh errors and provided a straightforward method to fix it by upgrading the package in PyCharm.