Write a Python program to find value $19$ in the list, and if it is present, replace it with $199.$ Only update the first occurrence of an item. And sum the resulting list. $(10$ pts$)$

$lis{t}_{f}o{r}_{q}02=[51,1,15,19,25,50,19]$

Using the above list given in the question $3,$ write a Python program to remove both the entries of $19.$ To achieve this solution, define a function called removeEntry$()$ and use for loop inside this function. $(10$ pts$)$

Write a Python program to extend the mainList by adding the secondList the extend method. $(10$ pts$)$

mainList $=[n,b,[c,[d,e,[n,o],i],s],q,y]$

$secondList=[g,k,j]$

Expected output list looks something like the following: $["$n$","$b$",["$c$",["$d$","$e$",["$n$","$o$","$g$","$k$","$j$"],"$i$"],"$s$"],"$q$","$y$"].$

Indexing hint:

mainList$[2]=[\text{'}$c$\text{'},[\text{'}$d$\text{'},\text{'}$e$\text{'},[\text{'}$n$\text{'},\text{'}$o$\text{'}],\text{'}$i$\text{'}],\text{'}$s$\text{'}]$

mainList $[2][1]=[\text{'}$d$\text{'},\text{'}$e$\text{'},[\text{'}$n$\text{'},\text{'}$o$\text{'}],\text{'}$i$\text{'}]$

mainList $[2][1][2]=[\text{'}$n$\text{'},\text{'}$o$\text{'}]$