code: 
  
  import numpy as np
  from cva import COLOR_BGR2GRAY, cvtColor, imread, imshow, waitKey
  
  from digital_image_processing.filters.convolve import img_convolve
  
  
  
  
  
  
  def 		_A		(		_lowercase   )				->   Optional[Any]:
  
  
       """simple docstring"""
  
  
       __UpperCamelCase   = np.array([[-1, 0, 1], [-2, 0, 2], [-1, 0, 1]]   )
       __UpperCamelCase   = np.array([[1, 2, 1], [0, 0, 0], [-1, -2, -1]]   )
  
       __UpperCamelCase   = np.abs(img_convolve(_lowercase				,     _lowercase   )   )
       __UpperCamelCase   = np.abs(img_convolve(_lowercase				,     _lowercase   )   )
       # modify the pix within [0, 255]
       __UpperCamelCase   = dst_x * 2_55 / np.max(_lowercase   )
       __UpperCamelCase   = dst_y * 2_55 / np.max(_lowercase   )
  
       __UpperCamelCase   = np.sqrt((np.square(_lowercase   )) + (np.square(_lowercase   ))   )
       __UpperCamelCase   = dst_xy * 2_55 / np.max(_lowercase   )
       __UpperCamelCase   = dst_xy.astype(np.uinta   )
  
       __UpperCamelCase   = np.arctana(_lowercase				,     _lowercase   )
       return dst, theta
  
  
  if __name__ == "__main__":
      # read original image
      __snake_case             =	imread('''../image_data/lena.jpg''')
      # turn image in gray scale value
      __snake_case             =	cvtColor(img, COLOR_BGR2GRAY)
  
      __snake_case       ,  __snake_case             =	sobel_filter(gray)
  
      # show result images
      imshow('''sobel filter''', sobel_grad)
      imshow('''sobel theta''', sobel_theta)
      waitKey(0)
  
  
  
style_context: 
  
  
  def 		_A		(		_lowercase   )				->   bool:
  
  
       """simple docstring"""
  
  
       if not isinstance(_lowercase				,     _lowercase   ):
            raise ValueError('Input series is not valid, valid series - [1, 2/3, 2]'   )
       if len(_lowercase   ) == 0:
            raise ValueError('Input list must be a non empty list'   )
       if len(_lowercase   ) == 1 and series[0] != 0:
            return True
       __UpperCamelCase   = []
       __UpperCamelCase   = len(_lowercase   )
       for i in range(0				,     _lowercase   ):
            if series[i] == 0:
                 raise ValueError('Input series cannot have 0 as an element'   )
            rec_series.append(1 / series[i]   )
       __UpperCamelCase   = rec_series[1] - rec_series[0]
       for index in range(2				,     _lowercase   ):
            if rec_series[index] - rec_series[index - 1] != common_diff:
                 return False
       return True
  
  
  
  
  
  
  def 		_A		(		_lowercase   )				->   float:
  
  
       """simple docstring"""
  
  
       if not isinstance(_lowercase				,     _lowercase   ):
            raise ValueError('Input series is not valid, valid series - [2, 4, 6]'   )
       if len(_lowercase   ) == 0:
            raise ValueError('Input list must be a non empty list'   )
       __UpperCamelCase   = 0
       for val in series:
            answer += 1 / val
       return len(_lowercase   ) / answer
  
  
  if __name__ == "__main__":
      import doctest
  
      doctest.testmod()
  
  
  