;-------------------------------------------------------------
;+
; NAME:
; AURORAX_CREATE_METADATA_FILTER
;
; PURPOSE:
; Create metadata filter object for searches
;
; EXPLANATION:
; The AuroraX ephemeris, data products, and conjunction searches can take
; metadata filters to help refine your search. This function provides
; an easy way to create a metadata filter object using a list of expressions.
;
; CALLING SEQUENCE:
; aurorax_create_metadata_filter(expressions)
;
; PARAMETERS:
; expressions the expressions to use for this metadata filter, list (use
; aurorax_create_metadata_filter_expressions() function to
; create the expression(s))
;
; OUTPUT:
; the metadata filter
;
; OUTPUT TYPE:
; a hash
;
; EXAMPLES:
; expression1 = aurorax_create_metadata_filter_expression('calgary_apa_ml_v1', list('classified as APA'),/OPERATOR_IN)
; expression2 = aurorax_create_metadata_filter_expression('calgary_apa_ml_v1_confidence', 95,/OPERATOR_GE)
; expressions = list(expression1, expression2)
; metadata_filters = aurorax_create_metadata_filter(expressions,/OPERATOR_AND)
;+
;-------------------------------------------------------------