old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  r"""
  This module implements signals objects which allow the user to load predefined
  images.
  
  * :class:`signals`: The base class of this module which contains a few methods
  that loads predefined image (the :meth:`lena` method) and some tools methods
  (the :meth:`rgb2gray` method)
  
  """
  
  import os
  import os.path
  import matplotlib.image as mpimg
  
  
  class signals(object):
      r"""
      This class is used to load image through adequated methods.
      """
  
      def __init__(self):
          pass
  
      def rgb2gray(self, rgb):
      	r"""
          Python version of the rgb2gray() matlab method. Convert RGB image or
          colormap to grayscale.
  
          Parameters
          ----------
          rgb : array_like
              Input image.
  
          Returns
          -------
          gray_scale : array_like
              The grayscale converted image.
  
          Examples
          --------
          >>> from pyunlocbox import signals
          >>> import matplotlib.pyplot as plt
          >>> s = signals.signals()
          >>> pic = s.lena()
          >>> plt.imshow(pic, cmap=plt.get_cmap('gray')) #doctest: +ELLIPSIS
          <matplotlib.image.AxesImage object at 0x...>
          >>> plt.show(block=False)
  
          """
          r, g, b = rgb[:, :, 0], rgb[:, :, 1], rgb[:, :, 2]
          gray = 0.2989 * r + 0.5870 * g + 0.1140 * b
          return gray
  
      def lena(self):
          img = mpimg.imread(os.path.dirname(os.path.realpath(__file__)) +
                             '/signals/lena.png')
          gray_scale = self.rgb2gray(img)
          return gray_scale
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  r"""
  This module implements signals objects which allow the user to load predefined
  images.
  
  * :class:`signals`: The base class of this module which contains a few methods
  that loads predefined image (the :meth:`lena` method) and some tools methods
  (the :meth:`rgb2gray` method)
  
  """
  
  import os
  import os.path
  import matplotlib.image as mpimg
  
  
  class signals(object):
      r"""
      This class is used to load image through adequated methods.
      """
  
      def __init__(self):
          pass
  
      def rgb2gray(self, rgb):
          r"""
          Python version of the rgb2gray() matlab method. Convert RGB image or
          colormap to grayscale.
  
          Parameters
          ----------
          rgb : array_like
              Input image.
  
          Returns
          -------
          gray_scale : array_like
              The grayscale converted image.
  
          Examples
          --------
          >>> from pyunlocbox import signals
          >>> import matplotlib.pyplot as plt
          >>> s = signals.signals()
          >>> pic = s.lena()
          >>> plt.imshow(pic, cmap=plt.get_cmap('gray')) #doctest: +ELLIPSIS
          <matplotlib.image.AxesImage object at 0x...>
          >>> plt.show(block=False)
  
          """
          r, g, b = rgb[:, :, 0], rgb[:, :, 1], rgb[:, :, 2]
          gray = 0.2989 * r + 0.5870 * g + 0.1140 * b
          return gray
  
      def lena(self):
          img = mpimg.imread(os.path.dirname(os.path.realpath(__file__)) +
                             '/signals/lena.png')
          gray_scale = self.rgb2gray(img)
          return gray_scale
  
subject: fix indent