Multiple definition of element '[REDACTED]' causes the content model 
to become ambiguous. A content model must be formed such that during 
validation of an element information item sequence, the particle 
contained directly, indirectly or implicitly therein with which to 
attempt to validate each item in the sequence in turn can be uniquely 
determined without examining the content or attributes of that item, 
and without any information about the items in the remainder of the 
sequence.