Assignment - Functions

What is definition of function?
What is the function call?
What is code block and how does it relate to a function?
Create a function that will take a string as an argument and greet the user. For example, if the function is called with "John", the function should return "Hello, John!".
Create a function that takes a string as an argument and returns a string with the argument value in reverse. For example, if the function is called with input "hello", the function should return "olleh". (Use a loop, not a method that does this in one step.)
What is default argument and how does it work?
What is scope and lifetime of a variable?
What is a return value?
What is return value of a function that does not have a return statement?
Given the following function, find mistakes in the code and explain what the function is supposed to do.
```
def foo(x):
    x * 2

x = 7
x = foo(x)
print(x)
```

Given the following code, find and correct the mistake in the code.

def bar(x):
    x += 1

def foo(x):
    bar(x)
    x *= 2

x = 7
foo(x)
print(x)

Given the following function, what is the return value of the function call foo(2)? Explain your answer.

def foo(x):
    if x > 5:
        return x
    else:
        return x + foo(x + 1)

Create a function that takes a list of numbers as an argument and returns the sum of the odd numbers in the list. (Use a loop, not a method that does this in one step.)
Create a function that takes a string as an argument and returns a dictionary with the count of each character in the string. For example, if the function is called with "hello", the function should return {'h': 1, 'e': 1, 'l': 2, 'o': 1}. (Use a loop, not a method that does this in one step.)
Create a function that takes a string as an argument and returns a dictionary with the count of each word in the string. For example, if the function is called with "hello world", the function should return {'hello': 1, 'world': 1}. (Use a loop, not a method that does this in one step.)
Create a function that takes a string as an argunment and returns True if string is a Palindrome else False. Palindrome is a word that reads the same backward as forward. For example, if the function is called with "elle" the function should return True, if function receives "Hello" it should return False

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