text: from molsysmt._private.exceptions import *
  from molsysmt._private.digestion import *
  
  def extract(item, atom_indices='all', structure_indices='all', output_filename=None, copy_if_all=True, check=True):
  
      if check:
  
          digest_item(item, 'file:mol2')
          atom_indices = digest_atom_indices(atom_indices)
          structure_indices = digest_structure_indices(structure_indices)
  
      if output_filename is None:
          output_filename = item
  
      if (atom_indices is 'all') and (structure_indices is 'all'):
  
          if copy_if_all or (output_filename!=item):
  
              raise NotImplementedError()
  
          else:
  
              raise NotImplementedError()
  
      else:
  
          raise NotImplementedError()
  
      return tmp_item
  
  