When a program encounters an exception during execution, it is terminated if the exception is not handled. By handling multiple exceptions, a program can respond to different exceptions without terminating it. In Python, try-except blocks can be used to catch and respond to one or multiple exceptions. In cases where a process raises more than one possible exception, they can all be handled using a single except clause.
The Python TypeError: unhashable type: 'list' usually means that a list is being used as a hash argument. This error occurs when trying to hash a list, which is an unhashable object. For example, using a list as a key in a Python dictionary will cause this error since dictionaries only accept hashable data types as a key. The standard way to solve this issue is to cast a list to a tuple, which is a hashable data type.
Apache Spark is now widely used in many enterprises for building high-performance ETL and Machine Learning pipelines. If the users are already familiar with Python then PySpark provides a python API for using Apache Spark. When users work with PySpark they often use existing python and/or custom Python packages in their program to extend and complement Apache Spark’s functionality. Apache Spark provides several options to manage these dependencies.