### 1. Print a Greeting Message

**Problem:** Write a function `greet()` that prints `"Hello, Python!"`.

**Explanation:** A simple function with no parameters.

**Example Output:**

```
Hello, Python!

```

***

### 2. Function to Add Two Numbers

**Problem:** Write a function `add(a, b)` that returns the sum of two numbers.

**Example Input:**

```
add(5, 7)

```

**Output:**

```
12

```

***

### 3. Function to Find Maximum of Two Numbers

**Problem:** Write a function `maximum(a, b)` that returns the larger number.

**Example Input:**

```
maximum(10, 15)

```

**Output:**

```
15

```

***

### 4. Function to Check Even or Odd

**Problem:** Write a function `is_even(n)` that returns `"Even"` if the number is even and `"Odd"` if it is odd.

**Example Input:**

```
is_even(7)

```

**Output:**

```
Odd

```

***

### 5. Function to Calculate Factorial

**Problem:** Write a function `factorial(n)` to calculate factorial of a number using a loop.

**Example Input:**

```
factorial(5)

```

**Output:**

```
120

```

***

### 6. Function to Check Prime Number

**Problem:** Write a function `is_prime(n)` that returns `True` if a number is prime, otherwise `False`.

**Example Input:**

```
is_prime(13)

```

**Output:**

```
True

```

***

### 7. Function to Find Sum of List

**Problem:** Write a function `sum_list(lst)` that returns the sum of all numbers in a list.

**Example Input:**

```
sum_list([2, 4, 6])

```

**Output:**

```
12

```

***

### 8. Function to Reverse a String

**Problem:** Write a function `reverse_string(s)` that returns the reversed string.

**Example Input:**

```
reverse_string("Python")

```

**Output:**

```
nohtyP

```

***

### 9. Function with Default Argument

**Problem:** Write a function `greet_person(name="Guest")` that prints `"Hello, <name>!"`.

**Example Input:**

```
greet_person("Alice")

```

**Output:**

```
Hello, Alice!

```

**Example Input (without argument):**

```
greet_person()

```

**Output:**

```
Hello, Guest!

```

***

### 10. Function to Count Vowels in String

**Problem:** Write a function `count_vowels(s)` that returns the number of vowels in a string.

**Example Input:**

```
count_vowels("Python is fun")

```

**Output:**

```
4

```

***

##

### 11. Function to Find Maximum in a List

**Problem:** Write a function `max_in_list(lst)` that returns the largest number in a list.

**Example Input:**

```
max_in_list([4,7,2,9,5])

```

**Output:**

```
9

```

***

### 12. Function to Calculate Power

**Problem:** Write a function `power(base, exp)` that returns `base` raised to the power of `exp`.

**Example Input:**

```
power(2, 3)

```

**Output:**

```
8

```

***

### 13. Function to Count Words in a Sentence

**Problem:** Write a function `count_words(sentence)` that returns the number of words in a sentence.

**Example Input:**

```
count_words("Python is fun to learn")

```

**Output:**

```
5

```

***

### 14. Function to Check Armstrong Number

**Problem:** Write a function `is_armstrong(n)` that returns `True` if a number is an Armstrong number, otherwise `False`.

**Example Input:**

```
is_armstrong(153)

```

**Output:**

```
True

```

***

### 15. Function to Check Palindrome String

**Problem:** Write a function `is_palindrome(s)` that returns `True` if a string is a palindrome, otherwise `False`.

**Example Input:**

```
is_palindrome("radar")

```

**Output:**

```
True

```

***

### 16. Function to Count Occurrences of Character

**Problem:** Write a function `count_char(s, ch)` that counts the number of times a character occurs in a string.

**Example Input:**

```
count_char("banana", "a")

```

**Output:**

```
3

```

***

### 17. Function to Merge Two Lists

**Problem:** Write a function `merge_lists(lst1, lst2)` that returns a combined list.

**Example Input:**

```
merge_lists([1,2,3], [4,5])

```

**Output:**

```
[1,2,3,4,5]

```

***

### 18. Function to Remove Duplicates from List

**Problem:** Write a function `remove_duplicates(lst)` that returns a list with duplicates removed.

**Example Input:**

```
remove_duplicates([1,2,2,3,3,3])

```

**Output:**

```
[1,2,3]

```

***

### 19. Function to Reverse a List

**Problem:** Write a function `reverse_list(lst)` that returns the reversed list.

**Example Input:**

```
reverse_list([1,2,3,4])

```

**Output:**

```
[4,3,2,1]

```

***

### 20. Function to Find Palindrome Numbers in a List

**Problem:** Write a function `palindrome_numbers(lst)` that returns a list of all palindrome numbers from a given list.

**Example Input:**

```
palindrome_numbers([121,123,454,567,787])

```

**Output:**

```
[121,454,787]

```

***

3. Function to Find Maximum of Two Numbers

 to calculate factorial of a number using a loop.

 that returns the sum of all numbers in a list.

 that returns the number of vowels in a string.

 that returns the largest number in a list.

13. Function to Count Words in a Sentence

 that returns the number of words in a sentence.

 if a number is an Armstrong number, otherwise 