code: def fcat(*fs):
      
      items = list()
      for f in fs:
          if isinstance(f, boolfunc.Function):
              items.append(f)
          elif isinstance(f, farray):
              items.extend(f.flat)
          else:
              raise TypeError("expected Function or farray")
      return farray(items)
docs: Concatenate a sequence of farrays.
  
      The variadic *fs* input is a homogeneous sequence of functions or arrays.