code: def _manual_lines(solver_name=None):
      """Brief solver manual.
  
      :param solver_name: (optional) name of the solver to request a manual from.
          If none is specified, a general manual and list of all registered solvers is returned.
  
      :result:
          * list of strings that contain the requested manual
          * solver name(s): name of the solver that was specified or list of all registered solvers.
  
      Raises ``KeyError`` if ``solver_name`` is not registered."""
      if solver_name:
          return solver_registry.get(solver_name).desc_full, [
              solver_name
          ]
      else:
          return (
              solver_registry.manual(),
              solver_registry.solver_names(),
          )
  
imports: import timeit
  import sys
  import operator
  from .None import functions
  from .None import solvers
  from .None import search_spaces
  from .solvers import solver_registry
  from .util import DocumentedNamedTuple
  from .constraints import wrap_constraints
label_desc: Use image node_id 1 for calling a global function with example usage: _manual_lines(solver_name) and returns: solver_registry,  list, solver_registry,  solver_registry