为什么来自MacPorts的ImageMagick不起作用，当来自Homebrew的imagemagick确实如此

Question

我已通过Homebrew安装修复了我的错误，但我想知道：为什么homebrew可以正常工作但macports没有？

如果我从MacPorts安装ImageMagick，即使我可以拨打＆＃34; convert＆＃34;我也会收到此错误从命令行：

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Python/2.7/site-packages/wand/image.py", line 20, in <module>
    from .api import MagickPixelPacket, libc, libmagick, library
  File "/Library/Python/2.7/site-packages/wand/api.py", line 205, in <module>
    'Try to install:\n  ' + msg)
ImportError: MagickWand shared library not found.
You probably had not installed ImageMagick library.
Try to install:
  port install imagemagick

我已经做过了！

如果我通过homebrew安装，我就无法再使用＆＃34; convert＆＃34;从命令行开始，但它与wand的{​​{1}}配合得很好。那是为什么？