Traceback (most recent call last):
  File "stack_overflow.py", line 16, in <module>
    image = create_captcha("GENE", shear=0.5)
  File "stack_overflow.py", line 8, in create_captcha
    font = ImageFont.truetype(r"Coval.otf", 22)
  File "/usr/local/lib/python2.7/site-packages/PIL/ImageFont.py", line 244, in truetype
    return FreeTypeFont(font, size, index, encoding)
  File "/usr/local/lib/python2.7/site-packages/PIL/ImageFont.py", line 133, in __init__
    self.font = core.getfont(font, size, index, encoding)
IOError: cannot open resource