df apply not working as expected #628

Describe the bug
df apply not working as expected

To Reproduce
Here is the code for reproduce the bug

let data = {
    "text": ['THIS','IS', 'IN','UPPERCASE'],
    "count": [34, -4, 5, 0],
    "rank": [20, 2, 30, 8]
}
let df = new dfd.DataFrame(data)
df.print()

df['text'].apply(x => x.toLowerCase(), {inplace:true})  // It should change the df['text'] to upper case
df.print()

Expected behavior
df['colums'].apply(x => x +1 , {inplace:true}) should mutate the coulmn according to lambda in apply, but it is not doing so.

Screenshots

Desktop (please complete the following information):

• OS: [Windows]
• Browser [chrome]
• Version [1.1.2]

Additional context

df['text'] = df['text'].apply(x =>x.toLowerCase()) working correctly.