Issue with 'particle' index and label prevents MSD calculation

[AWAshley93]

In trying to calculate the MSD from my particle positions, I get the error below. I did not have issues with this section before.

"ValueError: 'particle' is both an index level and a column label, which is ambiguous."

located in

~\anaconda3\lib\site-packages\trackpy\motion.py in ?(traj, mpp, fps, max_lagtime, statistic, pos_columns)
190 ids = []
191 msds = []
192 # Note: Index is set by msd, so we don't need to worry
193 # about conformity here.
--> 194 for pid, ptraj in traj.groupby('particle'):
195 msds.append(msd(ptraj, mpp, fps, max_lagtime, False, pos_columns))
196 ids.append(pid)
197 results = pandas_concat(msds, keys=ids)