Here, Python attempted to run the function frint, but could not determine what frint is since it's not a built-in function and it has not been previously defined by us either.

# data types - classes of data (e.g., string, int, float, Boolean, etc.), which include the properties and behaviors of instances of the data type (variables) # variable - an instance of a data type ...

Assignment expressions allow a value to be assigned to a variable, even a variable that doesn’t exist yet, in the context of an expression rather than as a stand-alone statement.

Assignment statements In Python, we use the = to assign a value to a variable, and we call = the assignment operator. The variable name is on the left-hand side of the assignment operator, and the ...

In programming—and computer science in general—an expression is something which can be evaluated—that is, a syntactically valid combination of constants, variables, functions, and operators which ...

Mypy will complain: mytest.py:13: error: Incompatible types in assignment ↪(expression has type "str", variable has type ↪"Optional[int]") Sure enough, you now can assign either None or an integer to ...