code: def trimcoef(c, tol=0):
      """
      Remove "small" "trailing" coefficients from a polynomial.
  
      "Small" means "small in absolute value" and is controlled by the
      parameter `tol`; "trailing" means highest order coefficient(s), e.g., in
      ``[0, 1, 1, 0, 0]`` (which represents ``0 + x + x**2 + 0*x**3 + 0*x**4``)
      both the 3-rd and 4-th order coefficients would be "trimmed."
  
      Parameters
      ----------
      c : array_like
          1-d array of coefficients, ordered from lowest order to highest.
      tol : number, optional
          Trailing (i.e., highest order) elements with absolute value less
          than or equal to `tol` (default value is zero) are removed.
  
      Returns
      -------
      trimmed : ndarray
          1-d array with trailing zeros removed.  If the resulting series
          would be empty, a series containing a single zero is returned.
  
      Raises
      ------
      ValueError
          If `tol` < 0
  
      See Also
      --------
      trimseq
  
      Examples
      --------
      >>> from numpy.polynomial import polyutils as pu
      >>> pu.trimcoef((0,0,3,0,5,0,0))
      array([0.,  0.,  3.,  0.,  5.])
      >>> pu.trimcoef((0,0,1e-3,0,1e-5,0,0),1e-3) # item == tol is trimmed
      array([0.])
      >>> i = complex(0,1) # works for complex
      >>> pu.trimcoef((3e-4,1e-3*(1-i),5e-4,2e-5*(1+i)), 1e-3)
      array([0.0003+0.j   , 0.001 -0.001j])
  
      """
      if tol < 0:
          raise ValueError("tol must be non-negative")
  
      [c] = as_series([c])
      [ind] = np.nonzero(np.abs(c) > tol)
      if len(ind) == 0:
          return c[:1] * 0
      else:
          return c[: ind[-1] + 1].copy()
  
imports: import operator
  import functools
  import warnings
  import numpy
  from numpy.core.multiarray import dragon4_positional, dragon4_scientific
  from numpy.core.umath import absolute
label_desc: Use image node_id 3 for calling a global function with example usage: trimcoef(c, tol) and returns: unknown, c