Python subprocess, subshells, and redirection

I want to use the magic of subshells and redirection with the python subprocess modu开发者_运维问答le, but it doesn't seem to work, complaining about unexpected tokens are the parenthesis. For example, the command

cat <(head tmp)

when passed to subprocess gives this

>>> subprocess.Popen("cat <(head tmp)", shell=True)
<subprocess.Popen object at 0x2b9bfef30350>
>>> /bin/sh: -c: line 0: syntax error near unexpected token `('
/bin/sh: -c: line 0: `cat <(head tmp)'

The <(head tmp) syntax is a bash feature called "process substitution". The basic/portable /bin/sh doesn't support it. (This is true even on systems where /bin/sh and /bin/bash are the same program; it doesn't allow this feature when invoked as plain /bin/sh so you won't inadvertently depend on a non-portable feature.)

>>> subprocess.Popen(["/bin/bash", "-c", "cat <(head tmp)"])
<subprocess.Popen object at 0x1004cca50>