How can modify this to do atleast 2 test cases for each function using doctest?

Question

def mystring(string):
def my_split(string,seperator=""):
lst=[ ]
for i in string:

if seperator==i:
continue
lst1=lst.append(i)

print(lst)
my_split(string,seperator="")
char=input("Character needed to count : ")

'''
Count the number of occurrences of a character in a given string
>>> count_char("animalplanet", 'a')
3
>>> count_char("animalplanet", 's')
0
'''
def count_char(string, char):

counter=string.count(char)
print(counter)
count_char(string, char)

'''Count the number of occurrences of a character in a given string

'''
index=int(input("Index of the character needed to remove : "))
def remove_char(string, index):

string = string[:index] + string[index + 1:]
print(string)
remove_char(string, index)