code: def sphere_average(dset,x,y,z,radius=1):
      '''returns a list of average values (one for each subbrick/time point) within the coordinate ``(x,y,z)`` (in RAI order) using a sphere of radius ``radius`` in ``dset``'''
      return_list = []
      if isinstance(dset,basestring):
          dset = [dset]
      for d in dset:
          return_list += [float(a) for a in subprocess.check_output(['3dmaskave','-q','-dball',str(x),str(y),str(z),str(radius),d],stderr=subprocess.PIPE).split()]
      return return_lisf sphere_average(dset,x,y,z,radius=1):
      '''returns a list of average values (one for each subbrick/time point) within the coordinate ``(x,y,z)`` (in RAI order) using a sphere of radius ``radius`` in ``dset``'''
      return_list = []
      if isinstance(dset,basestring):
          dset = [dset]
      for d in dset:
          return_list += [float(a) for a in subprocess.check_output(['3dmaskave','-q','-dball',str(x),str(y),str(z),str(radius),d],stderr=subprocess.PIPE).split()]
      return return_list
docs: returns a list of average values (one for each subbrick/time point) within the coordinate ``(x,y,z)`` (in RAI order) using a sphere of radius ``radius`` in ``dset``