Set parameter organism as required wihtout an default value

pipeline.nf

@@ -55,10 +55,10 @@
 	params.best_motif = 3 // Top n motifs per cluster
 
 //creating_gtf
-	params.organism="hg38"
+	params.organism=""
 	params.tissue=""
 
-if (params.bigwig == "" || params.bed == "" || params.genome_fasta == "" || params.motif_db == "" || params.config == "" || "${params.help}" != "0"){
+if (params.bigwig == "" || params.bed == "" || params.organism == "" || params.genome_fasta == "" || params.motif_db == "" || params.config == "" || "${params.help}" != "0"){
 log.info """
 Usage: nextflow run pipeline.nf --bigwig [BigWig-file] --bed [BED-file] --genome_fasta [FASTA-file] --motif_db [MEME-file] --config [UROPA-config-file]
 
@@ -70,6 +70,7 @@ Required arguments:
 	--config		 Path to UROPA configuration file
 	--create_known_tfbs_path Path to directory where output from tfbsscan (known motifs) are stored.
 				 Path can be set as tfbs_path in next run. (Default: './')
+ 	--organism 		 Input organism [hg38 | hg19 | mm9 | mm10]
 	--out			 Output Directory (Default: './out/')
 
 Optional arguments:
@@ -115,7 +116,6 @@ Optional arguments:
 	--motif_similarity_thresh FLOAT	Threshold for motif similarity score (Default: 0.00001)
 
 	Creating GTF:
-	--organism [hg38 | hg19 | mm9 | mm10]	Input organism
 	--tissues List/String 	List of one or more keywords for tissue-/category-activity, categories must be specified as in JSON
 				config
 All arguments can be set in the configuration files