Weird parameter in Numpy method [duplicate]

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• foggy on asterisk in python 3 answers

In some MachineLearning tutorial I discovered the following code:

trX = np.linspace(-1, 1, 101)
trY = 2 * trX + np.random.randn(*trX.shape) * 0.33
                                ^
                                |___ what does this do?

At first I thought this is a mistake but the code is working perfectly and if I delete the * in *trX.shape the code generates errors. However, I am unable to figure out what exactly this operator does to the parameter trX.shape. If I try *someArray.shape in IPython it always throws a syntax error.

Is it some special "trick operator" somehow unpacking the shape and converting it to an integer? (since random.randn awaits an integer)