Assert statements are a convenient way to insert debugging  assertions into a program.

More information about the assert statement: https://docs.python.org/3/reference/simple_stmts.html#assert

The assert statement

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In Python, all exceptions must be instances of a class that derives from BaseException. In a try statement with an except clause that mentions a particular class, that clause also handles any exception classes derived from that class (but not exception classes from which it is derived). Two exception classes that are not related via subclassing are never equivalent, even if they have the same name.

The built-in exceptions listed below can be generated by the interpreter or built-in functions. Except where mentioned, they have an “associated value” indicating the detailed cause of the error. This may be a string or a tuple of several items of information (e.g., an error code and a string explaining the code). The associated value is usually passed as arguments to the exception class’s constructor.

User code can raise built-in exceptions. This can be used to test an exception handler or to report an error condition “just like” the situation in which the interpreter raises the same exception; but beware that there is nothing to prevent user code from raising an inappropriate error.

The built-in exception classes can be subclassed to define new exceptions; programmers are encouraged to derive new exceptions from the Exception class or one of its subclasses, and not from BaseException. More information on defining exceptions is available in the Python Tutorial under User-defined Exceptions.

Built-In Exceptions

Assertion Error

Raised when an attribute reference or assignment fails. When an object does not support attribute references or attribute assignments at all, TypeError is raised.

AttributeError

Raised when the input() function hits an end-of-file condition (EOF) without reading any data. N.B.: the io.IOBase.read() and io.IOBase.readline() methods return an empty string when they hit EOF.

EOFError

Raised when the input() function hits an end-of-file condition (EOF) without reading any data. (N.B.: the io.IOBase.read() and io.IOBase.readline() methods return an empty string when they hit EOF.)

FloatingPointError

Raised when the import statement has troubles trying to load a module. Also raised when the “from list” in from ... import has a name that cannot be found.

The name and path attributes can be set using keyword-only arguments to the constructor. When set they represent the name of the module that was attempted to be imported and the path to any file which triggered the exception, respectively.

ImportError

Raised when a sequence subscript is out of range. (Slice indices are silently truncated to fall in the allowed range; if an index is not an integer, TypeError is raised.)

IndexError

This exception is derived from RuntimeError. It is raised when the interpreter detects that the maximum recursion depth (see sys.getrecursionlimit()) is exceeded.

RecursionError

Raised when the parser encounters a syntax error. This may occur in an import statement, in a call to the built-in functions exec() or eval(), or when reading the initial script or standard input (also interactively).

The str() of the exception instance returns only the error message.

filename
The name of the file the syntax error occurred in.

lineno
Which line number in the file the error occurred in. This is 1-indexed: the first line in the file has a lineno of 1.

offset
The column in the line where the error occurred. This is 1-indexed: the first character in the line has an offset of 1.

text
The source code text involved in the error.

SyntaxError

https://docs.python.org/3/library/exceptions.html

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