code: def dmp_expand(polys, u, K):
      """
      Multiply together several polynomials in ``K[X]``.
  
      Examples
      ========
  
      >>> from sympy.polys import ring, ZZ
      >>> R, x,y = ring("x,y", ZZ)
  
      >>> R.dmp_expand([x**2 + y**2, x + 1])
      x**3 + x**2 + x*y**2 + y**2
  
      """
      if not polys:
          return dmp_one(u, K)
  
      f = polys[0]
  
      for g in polys[1:]:
          f = dmp_mul(f, g, u, K)
  
      return 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 64 for calling a global function with example usage: dmp_expand(polys, u, K) and returns: f, dmp_one