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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def load_to_array(self, keys):
 """ This loads the data contained in the catalogue into a numpy array. The method works only for float data :param keys: A list of keys to be uploaded into the array :type list: """

        # Preallocate the numpy array
        data = np.empty((len(self.data[keys[0]]), len(keys)))
        for i in range(0, len(self.data[keys[0]])):
            for j, key in enumerate(keys):
                data[i, j] = self.data[key][i]
        return data