Key takeaways

1. The print() function is a built-in function. It prints/outputs a specified message to the screen/console window
2. Built-in functions, contrary to user-defined functions, are always available and don't have to be imported. Python 3.8 comes with 69 built-in functions. You can find their full list provided in alphabetical order in the Python Standard Library
3. To call a function (this process is known as function invocation or function call), You need to use the function name followed by parentheses. You can pass arguments into function by placing them inside the parentheses. You can pass arguments into a function by placing them inside the parentheses. You must separate arguments with a comma, e.g., print ("Hello,", "world!"). an "empty" print() function outputs an empty line to the screen. 
4. Python strings are delimited with quotes, e.g., "I am a string" (double quotes), or 'I am a string, too' (single quotes)
5. Computer programs are collections of instructions. An instruction is a command to perform a specific task when executed. e.g, to print a certain message to the screen. 
6. In Python strings the backslash (\) is a special character which announces that the next character has a different meaning, e.g. \n (the newline character) starts a new output line. 
7. Positional arguments are the ones whose meaning is dictated by their position, e.g., the second argument is outputted after the first, the third is outputted after the second, etc. 
8. The end and sep parameteres can be used for formatting the output of the print() function. The sep parameter specifies the separator between the outputted arguments (e.g., print ('H", "E", "L","L", "O", sep="-") wherease the end paremeter specifies what to print at the end of the print statement.