function _curry1(fn) {
	  return function f1(a) {
	    if (arguments.length === 0 || _isPlaceholder(a)) {
	      return f1;
	    } else {
	      return fn.apply(this, arguments);
	    }
	  };
	}
function _curry1(fn) {
	  return function f1(a) {
	    if (arguments.length === 0 || _isPlaceholder(a)) {
	      return f1;
	    } else {
	      return fn.apply(this, arguments);
	    }
	  };
	}
function _curry1 ( fn ) { return function f1 ( a ) { if ( arguments . length === 0 || _isPlaceholder ( a ) ) { return f1 ; } else { return fn . apply ( this , arguments ) ; } } ; }
Optimized internal one-arity curry function.

@private
@category Function
@param {Function} fn The function to curry.
@return {Function} The curried function.
Optimized internal one - arity curry function .