Types of occurrences of the entity type in the document. This
represents the number of instances, not mentions, of an entity. For
example, a bank statement might only have one account_number,
but this account number can be mentioned in several places on the
document. In this case, the account_number is considered a
REQUIRED_ONCE entity type. If, on the other hand, we expect a
bank statement to contain the status of multiple different accounts
for the customers, the occurrence type is set to
REQUIRED_MULTIPLE.
Values:
OCCURRENCE_TYPE_UNSPECIFIED (0):
Unspecified occurrence type.
OPTIONAL_ONCE (1):
There will be zero or one instance of this
entity type. The same entity instance may be
mentioned multiple times.
OPTIONAL_MULTIPLE (2):
The entity type will appear zero or multiple
times.
REQUIRED_ONCE (3):
The entity type will only appear exactly
once. The same entity instance may be mentioned
multiple times.
REQUIRED_MULTIPLE (4):
The entity type will appear once or more
times.
