class_docstr: Simple Fourier transform for time series.
  
  The implementation is based on the real fast fourier transform from numpy.fft.rfft
  Returns pd.Series of amplitudes of integer range frequencies.
  Even-Sampling of data is assumed and frequency range converted to integer.
  
  Examples
  --------
  >>> from sktime.transformations.series.fourier import FourierTransform
  >>> from sktime.datasets import load_airline
  >>> X = load_airline()
  >>> transformer = FourierTransform()
  >>> X_ft = transformer.fit_transform(X)
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code: def __init__(self):
      super().__init__()
  
file_path: sktime/sktime/transformations/series/fourier.py
imports: import warnings
  from typing import List, Optional
  import numpy
  import pandas
  from numpy.fft import rfft
  from sktime.transformations.base import BaseTransformer
label_desc: Use image node_id 1 to create a new FourierTransform object from inherited base classes: BaseTransformer with example: obj = FourierTransform()