'pip' is the package installer for Python. It's used to install and manage software packages written in Python.

Variable names cannot start with a digit in Python, so "123myvar" is not a valid variable name.

When a Python module is imported, the code in the module is executed after importing. This allows you to use the module's functionality.

Using module aliases (aliases) in Python can make your code more readable and prevent naming conflicts when dealing with long module names or avoiding conflicts.

.py files contain Python source code, while .pyc files contain bytecode. Bytecode files (.pyc) are generated from source code (.py) to improve execution speed. The bytecode is platform-independent and can be executed faster.

NoSuchElementError is not a built-in exception in Python. The other options, ValueError, ImportError, and KeyError, are all common built-in exceptions in Python.

In Python, the keyword used to define a new class is 'class.' You use it to create a blueprint for objects with attributes and methods.

In general, a loop with a high complexity condition is more efficient than using nested loops. Nested loops can quickly lead to exponential increases in time complexity, making them less efficient for most scenarios. However, the efficiency depends on the specific use case and how well the code is optimized.

If an 'if' condition is false, the code will skip to the next sequential condition or the 'else' block if one is provided.

To flatten a list of lists, you can use the 'zip()' function within a list comprehension. It combines elements from multiple lists into pairs, effectively flattening them.