PyCharm getitem warning for functions with arrays

Pycharm has type hinting features that may be of use.

For example in this case, the following code makes the errors go away:

import numpy as np

def get_ydata(xdata):
    ydata = xdata ** 2  # type: np.ndarray
    for i in range(len(ydata)):
        print(ydata[i])
    return ydata

Recent python versions also include support for type annotations

import numpy as np
def get_ydata(xdata: np.ndarray):
    ...

TL;DR Cast it using list()

Its late, still,

I had similar problem with some other code.

I could solve it by something similar to

def get_ydata(xdata):
    ydata = list(xdata ** 2)
    for i in range(len(ydata)):
        print ydata[i]
    return ydata

Consider the accepted answer. Comments on my answer are valid.