Relations
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# standards (one to many) attendances
# students (one to many) attendances

# fees_groups (one to many) fees_masters
# fees_types (one to one) fees_masters

# students (one to many) fees_assings
# standrds (one to many) fees_assings
# fees_masters (one to many) fees_assings

# fees_assings (one to many) fees_collects