The type(object) function is a built-in Python function that returns the type of given object. It is useful when you want to check the class of an object, whether it is a built-in data type or a custom class you've created.

Using type() can be helpful when you want to determine the type of an object while debugging or understanding unfamiliar code. But remember that the isinstance() function might be a better fit for such checks.

isinstance(object, class) is a built-in Python function that checks if an object is an instance of a specified class or a subclass of that class. It returns a boolean value. True if the object is an instance of the given class or a subclass, and False if it isn't.

The function takes two arguments. The object that we want to check, and the class (or a tuple of classes) to check for. When providing a tuple as a second argument, the syntax looks like that - isinstance(object, (class_A, class_B, ...))

string.isdigit() is a built-in method that can be called on string, byte, and bytearray objects. It checks if a given object contains only digits (numeric characters). It returns a boolean value.

Please note that decimal points and negative signs are not considered digits, so they will cause the isdigit() method to return False.

string.isalpha() is a method that we can call on string, byte, and bytearray objects. It checks if a given object contains only letters or rather - alphabetic characters.

Parameters:

• value: The element to check for alphabetic characters.

This method returns a boolean (True or False) depending on the object contents.

It is worth noting that special characters existing in some languages are also considered alphabetic characters. So they won't trigger a False return by themselves.

Spaces, numbers, and symbols will cause the method to return False.

collection.index(value, start=None, end=None) is a built-in method that returns an index of a provided element in the data structure that it was called on.

It can be called only on ordered collections like list, tuple, and string.

Method index() also accepts two optional index argument between which it will be looking for a given value. The method returns the index of the first occurrence of the specified element.

We need to remember that if the element is not in a given collection we will receive ValueError!

Parameters:

• value: The element whose index you want to find.

• start (optional): The starting index to search from.

• end (optional): The ending index (exclusive) for the search.

iterable.count(value, start=None, end=None) is a built-in function that returns the count number of elements in your object. It can be called on the following data structures - list, tuple, string, byte, bytearray, and range objects. The count() function requires value argument that specifies what are we looking for and on some objects we can also provide indexes between which we want to count elements.

Parameters:

• value: The element to count within the iterable.

• start (optional): The starting index of the range to count - int. Default is 0.

• end (optional): The ending index (exclusive) of the range to count - int. Default is the length of the iterable.

string.replace(old: str, new: str, count: int) is a built-in function used to replace occurrences of a specific substring in a string with another substring. It also accepts the optional argument count that needs to be an integer. If provided, it will replace only count first occurrences of a provided substring. Remember that replace() is case-sensitive!

Arguments:

• old: The substring to be replaced.

• new: The substring to replace old with.

• count (optional): The maximum number of occurrences to replace. Defaults to replacing all occurrences.

round(number, ndigits) is a built-in function used for rounding numbers in Python.

number: The number to round (can be a float or int).

ndigits (optional): Specifies the number of decimal places to round to. It can be:

• positive integer: Round to the specified number of decimal places.

• negative integer: Round to the left of the decimal point.

• None (default): Round to the nearest integer.