old_contents: from .pwlf import PiecewiseLinFit  # noqa F401
  try:
      import tensorflow as tf  # noqa F401
      from .pwlftf import PiecewiseLinFitTF  # noqa F401
  except ImportError:
      print('Warning: Install tensorflow to have access to PiecewiseLinFitTF.')
  import os  # noqa F401
  
  # add rudimentary version tracking
  VERSION_FILE = os.path.join(os.path.dirname(__file__), 'VERSION')
  __version__ = open(VERSION_FILE).read().strip()
  
new_contents: from .pwlf import PiecewiseLinFit  # noqa F401
  try:
      import tensorflow as tf  # noqa F401
      from .pwlftf import PiecewiseLinFitTF  # noqa F401
  except ImportError:
      pass
  import os  # noqa F401
  
  # add rudimentary version tracking
  VERSION_FILE = os.path.join(os.path.dirname(__file__), 'VERSION')
  __version__ = open(VERSION_FILE).read().strip()
  
subject: remove tensorflow import warning