parameters: (self, section_id)
docstring: Enters a conditional section.
  
      Conditional sections define an entry node, and one or more branches.
  
      Args:
        section_id: Hashable, the same node that will be used in calls to the
          section_id arg passed to new_cond_branch
docstring_summary: Enters a conditional section.
docstring_tokens: Enters a conditional section .
function: def enter_cond_section(self, section_id):
      """Enters a conditional section.
  
      Conditional sections define an entry node, and one or more branches.
  
      Args:
        section_id: Hashable, the same node that will be used in calls to the
          section_id arg passed to new_cond_branch
      """
  
      assert section_id not in self.cond_entry
      assert section_id not in self.cond_leaves
      self.cond_leaves[section_id] = []
function_tokens: def enter_cond_section ( self , section_id ) : assert section_id not in self . cond_entry assert section_id not in self . cond_leaves self . cond_leaves [ section_id ] = [ ]