Error importing classes (source code > 72 characters)

What causes this issue?

You tried to import a piece of source code that is wider than 72
characters. However, the Class Builder's import function only supports
source code that is a maximum of 72 characters wide.
Create appropriate line breaks in the source code in the ABAP Editor;
then import the local classes.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.