This class represents a time period during the typical week during which the Provider is available. For example, if Dr. Smith works at Radiology Associates' Elm street location on Mondays, Wednesdays, and Fridays from 9 to 5, during which she normally takes lunch from 12-1, there will be six instances of this class, one for Monday with a start time of 9:00 AM and an end time of 12:00 PM, one for Monday from start time of 1:00 PM and an end time of 5:00 PM, and similarly for Wednesday and Friday. Alternatively, the provider may be scheduled in shifts (e.g., morning shift, evening shift). Because either the start and end times or the shifts may be used, all three properties are optional. The appointment window size property indicates the number of minutes that make up a schedulable block of time, for example, Dr. Smith may be scheduled in 15 minute increments. Note that this class is used to schedule Providers and Healthcare Services independent of a Provider (e.g., scheduling an MRI without knowing or caring in advances the human practitioner who will perform the MRI). "A collection of times that the Service Site is available." - HL7 FHIR, PractitionerRole.availableTime "A collection of times that the Service Site is available." - HL7 FHIR, HealthcareService.availableTime