File "<ipython-input-17-d70cd47a624a>", line 3 return arr ^ IndentationError: expected an indented block

This error message is indicating that there is an indentation problem in the code. In Python, indentation is used to group statements, so it is important to make sure that the code is indented correctly.

In this case, it seems that there is a problem with the indentation of the `return` statement. The `return` statement should be indented to be at the same level as the `if` statement, like this:

def remove_duplicates(arr):
    result = []
    for item in arr:
        if item not in result:
            result.append(item)
    return result

Make sure that all the statements in your code are indented correctly according to their level of nesting.