Upload several files and save to database

Hello, 
I need help!!
I have this field to upload documents to a database

a!fileUploadField(
 label: "Document",
 labelPosition: "ADJACENT",
 /*maxSelections: 1,*/
 value: ri!newDo.docum,
 saveInto:
 {
 ri!newSoli.documentation,
 ri!newDo.docum,
 a!save(ri!newDo.day,now())
 },
 target: cons!C_FLD_document,
 validations: {}
 )

What I want to achieve is that when uploading several documents I can do it and it does not appear
"Expression evaluation error in rule 'cpro_i_nuevasolicitud' at 
function a!fileUploadField [line 146]: Error in a!forEach() 
expression during iteration 1: Expression evaluation error at 
function fn!content_appian_internal 
[line 12]: Null Arguments are Invalid"

THANKS