Is your feature request related to a problem? Please describe.
Meetings and unscheduled calls, apart from emails and IMs, are critical components to understand user collaboration behaviors and are suggested to be added to the flexibility index analysis.

Describe the solution you'd like
Have meetings and unscheduled calls included in the signal extraction. For example, enable users to write, signals = c("email", "IM", "Meetings", "Unscheduled_calls") and extract signals accordingly.