<｜begin▁of▁sentence｜>### Instruction:
Given a time series of numerical values, how can we keep track of the number of elements for which we are calculating a running mean without storing all the individual elements?
### Response:
from pyinform.runningmean import RunningMean

# Create a RunningMean instance
running_mean = RunningMean()

# Add some values
running_mean.push(10)
running_mean.push(20)
running_mean.push(30)

# Get the number of items added to the RunningMean instance
length = len(running_mean)

# Print the length
print('Number of items:', length)
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