human
I am working on the file "Day 1 - Unit 1.3.ipynb".
The first task is:
9. Python functions

Sometimes, a portion of code is reused over and over again in the entire script. To prevent repetitive coding, we are able to define our own custom defined functions using the def keyword. When invoked, functions will instruct the computer to perform a set list of instructions, possibly returning an output at the end. Functions can also be pre-defined and saved in another file (with extension .py) so that it can be used for another project. 
You will have encountered many pre-defined functions in Python up to now. Functions like print, len, etc... But there are many other pre-built functions in Python which are extremely useful and makes code more transparent and readable.
We will also encounter what is known as anonymous functions which are defined using the lambda keyword. These are short functions and can only be defined in one line of code. While technically def does what lambda does, nevertheless lambda allows for less pendantic and more natural style of coding. You will encounter anonymous functions alot when working with pandas especially when cleaning up data frames. 
Finally we introduce what is perhaps one of the more important concepts in Python programming: List comprehensions. These are syntatical shortcuts for the for loop which translate not only to better code style, but faster scripts. 
9.1 Learning objectives
The objectives of this unit are:

To use the def keyword to defined functions. 

Recall the terms  arguments, keyword arguments, the signature of a function. 

To use lambda to define anonymous functions. 

To use build in  functions: zip and enumerate.  

To learn how to refactor for loops into list comprehension statements. 

9.2 Let's build our own functions
All functions are defined using the def keyword. In general, the format of function definition looks like this: 
def my_function_name(arg_1, arg_2, ..., arg_n) :

    code

    return &lt;something, or None&gt;

First, we tell Python that we are going to define a function by typing out def. Then we...
Can you write Python code for it?

Give me a known as anonymous functions which are defined using the lambda keyword?
assistant
#Here is known as anonymous functions which are defined using the lambda keyword.

# Our first function

def my_first_function():
    pass