Exercise $6\mathrm{.}4\mathrm{.}3$ Remove Duplicates

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Write a python function what will remove all the duplicated elements from the list. The function will take the

list of strings as its parameter and return the list containing unique elements.

For Example,

remove$\_$duplicate$([1,2,3,4,2,5,4,6])$ must return $[1,2,3,4,5,6]$

remove$\_$duplicate$([\text{'}$apple$\text{'},$ 'banana', 'orange', 'apple', 'mango', 'banana'$]$ must return

$[\text{'}$apple$\text{'},$ 'banana', 'orange', 'mango' $]$

remove$\_$duplicate$([\text{'}$Apple$\text{'},$ 'baNana', 'orange', 'apple', 'mango', 'banana'$]$ must return

$[\text{'}$apple$\text{'},$ 'banana', 'orange', 'mango' $]$

Pay attention to the order of items in the returned list. The presence of a letter in the list in any case does not

change the item. For example, Banana & baNana are the same.

$"""$

#DON'T REMOVE!!

list$1=[1,2,3,4,2,5,4,6]$

list$2=[\text{'}$apple$\text{'},$ 'banana', 'orange', 'apple', 'mango', 'banana'$]$

list$3=[\text{'}$Apple$\text{'},$ 'baNana', 'orange', 'apple', 'mango', 'banana'$]$

# Complete the following function

def remove$\_$duplicate$($a$\_$list$)$:

return