(obspy) sanjay@SanjayNCS:~/Downloads$ python3.7 probabilistic_power_spectral_density2.py 
/home/sanjay/anaconda2/envs/obspy/lib/python3.7/site-packages/obspy/signal/spectral_estimation.py:968: UserWarning: Error getting response from provided metadata:
AttributeError: 'str' object has no attribute 'format_seed'
Skipping time segment(s).
  warnings.warn(msg)
Traceback (most recent call last):
  File "probabilistic_power_spectral_density2.py", line 15, in <module>
    ppsd.plot(cmap=pqlx)
  File "/home/sanjay/anaconda2/envs/obspy/lib/python3.7/site-packages/obspy/signal/spectral_estimation.py", line 1905, in plot
    self.__check_histogram()
  File "/home/sanjay/anaconda2/envs/obspy/lib/python3.7/site-packages/obspy/signal/spectral_estimation.py", line 816, in __check_histogram
    raise Exception(msg)
Exception: No data accumulated