def oscltx(state, et, mu):
state = stypes.toDoubleVector(state)<EOL>et = ctypes.c_double(et)<EOL>mu = ctypes.c_double(mu)<EOL>elts = stypes.emptyDoubleVector(<NUM_LIT:20>)<EOL>libspice.oscltx_c(state, et, mu, elts)<EOL>return stypes.cVectorToPython(elts)[<NUM_LIT:0>:<NUM_LIT:11>]<EOL>
Determine the set of osculating conic orbital elements that 
corresponds to the state (position, velocity) of a body at some 
epoch. In additional to the classical elements, return the true 
anomaly, semi-major axis, and period, if applicable. 

https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/oscltx_c.html

:param state: State of body at epoch of elements. 
:type state: 6-Element Array of floats
:param et: Epoch of elements. 
:type et: float
:param mu: Gravitational parameter (GM) of primary body. 
:type mu: float
:return: Extended set of classical conic elements.