code: def create_backgrounds(outdir, background=None, genome="hg38", width=200, custom_background=None):
      
      if background is None:
          background = ["random"]
          nr_sequences = {}
  
      # Create background for motif prediction
      if "gc" in background:
          pred_bg = "gc"
      else:
          pred_bg = background[0]
      
      create_background(
                      pred_bg, 
                      os.path.join(outdir, "prediction.fa"), 
                      os.path.join(outdir, "prediction.bg.fa"), 
                      genome=genome, 
                      width=width,
                      custom_background=custom_background)
  
      # Get background fasta files for statistics
      bg_info = {}
      nr_sequences = {}    
      for bg in background:
          fname = os.path.join(outdir, "bg.{}.fa".format(bg))
          nr_sequences[bg] = create_background(
                                          bg, 
                                          os.path.join(outdir, "validation.fa"), 
                                          fname, 
                                          genome=genome, 
                                          width=width,
                                          custom_background=custom_background)
  
          bg_info[bg] = fname
      return bg_info
docs: Create different backgrounds for motif prediction and validation.
  
      Parameters
      ----------
      outdir : str
          Directory to save results.
      
      background : list, optional
          Background types to create, default is 'random'.
  
      genome : str, optional
          Genome name (for genomic and gc backgrounds).
  
      width : int, optional
          Size of background regions
  
      Returns
      -------
      bg_info : dict
          Keys: background name, values: file name.