code: def manual(solver_name=None):
      """Prints the manual of requested solver.
  
      :param solver_name: (optional) name of the solver to request a manual from.
          If none is specified, a general manual is printed.
  
      Raises ``KeyError`` if ``solver_name`` is not registered."""
      if solver_name:
          man = solver_registry.get(solver_name).desc_full
      else:
          man = solver_registry.manual()
      print("\n".join(man))
  
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 3 for calling a global function with example usage: manual(solver_name) without return types