code: def boolargs_from_apprxstr(approximant_strs):
      
      if not isinstance(approximant_strs, list):
          approximant_strs = [approximant_strs]
      return [tuple(arg.split(':')) for arg in approximant_strs]
docs: Parses a list of strings specifying an approximant and where that
      approximant should be used into a list that can be understood by
      FieldArray.parse_boolargs.
  
      Parameters
      ----------
      apprxstr : (list of) string(s)
          The strings to parse. Each string should be formatted `APPRX:COND`,
          where `APPRX` is the approximant and `COND` is a string specifying
          where it should be applied (see `FieldArgs.parse_boolargs` for examples
          of conditional strings). The last string in the list may exclude a
          conditional argument, which is the same as specifying ':else'.
  
      Returns
      -------
      boolargs : list
          A list of tuples giving the approximant and where to apply them. This
          can be passed directly to `FieldArray.parse_boolargs`.