code: def dmp_l2_norm_squared(f, u, K):
      """
      Returns squared l2 norm of a polynomial in ``K[X]``.
  
      Examples
      ========
  
      >>> from sympy.polys import ring, ZZ
      >>> R, x,y = ring("x,y", ZZ)
  
      >>> R.dmp_l2_norm_squared(2*x*y - x - 3)
      14
  
      """
      if not u:
          return dup_l2_norm_squared(f, K)
  
      v = u - 1
  
      return sum([dmp_l2_norm_squared(c, v, K) for c in f])
  
imports: from sympy.polys.densebasic import dup_slice, dup_LC, dmp_LC, dup_degree, dmp_degree, dup_strip, dmp_strip, dmp_zero_p, dmp_zero, dmp_one_p, dmp_one, dmp_ground, dmp_zeros
  from sympy.polys.polyerrors import ExactQuotientFailed, PolynomialDivisionFailed
label_desc: Use image node_id 62 for calling a global function with example usage: dmp_l2_norm_squared(f, u, K) and returns: sum, dup_l2_norm_squared