@spiceErrorCheck<EOL>def twopi():
return libspice.twopi_c()<EOL>
Return twice the value of pi
(the ratio of the circumference of a circle to its diameter).

http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/twopi_c.html

:return: Twice the value of pi.
:rtype: float