code: def normalize(signal):
      """
      Normalize the signal to have maximum amplitude.
  
      Parameters
      ----------
      signal : numpy array
          Signal to be normalized.
  
      Returns
      -------
      numpy array
          Normalized signal.
  
      Notes
      -----
      Signals with float dtypes cover the range [-1, +1], signals with integer
      dtypes will cover the maximally possible range, e.g. [-32768, 32767] for
      np.int16.
  
      The signal is returned with the same dtype, thus rounding errors may occur
      with integer dtypes.
  
      """
      # scaling factor to be applied
      scaling = float(np.max(np.abs(signal)))
      if np.issubdtype(signal.dtype, np.integer):
          if signal.dtype in (np.int16, np.int32):
              scaling /= np.iinfo(signal.dtype).max
          else:
              raise ValueError(
                  "only float and np.int16/32 dtypes supported, "
                  "not %s." % signal.dtype
              )
      # Note: np.asanyarray returns the signal's ndarray subclass
      return np.asanyarray(signal / scaling, dtype=signal.dtype)
  
imports: from __future__ import absolute_import, division, print_function
  import warnings
  import numpy
  from ..processors import BufferProcessor, Processor
  from ..utils import integer_types
label_desc: Use image node_id 4 for calling a global function with example usage: normalize(signal) and returns: np