code: def get_bond_length(sp1, sp2, bond_order=1):
      
      sp1 = Element(sp1) if isinstance(sp1, str) else sp1
      sp2 = Element(sp2) if isinstance(sp2, str) else sp2
      try:
          all_lengths = obtain_all_bond_lengths(sp1, sp2)
          return all_lengths[bond_order]
      # The ValueError is raised in `obtain_all_bond_lengths` where no bond
      # data for both elements is found. The KeyError is raised in
      # `__getitem__` method of `dict` builtin class where although bond data
      # for both elements is found, the data for specified bond order does
      # not exist. In both cases, sum of atomic radius is returned.
      except (ValueError, KeyError):
          warnings.warn("No order %d bond lengths between %s and %s found in "
                        "database. Returning sum of atomic radius."
                        % (bond_order, sp1, sp2))
          return sp1.atomic_radius + sp2.atomic_radius
docs: Get the bond length between two species.
  
      Args:
          sp1 (Specie): First specie.
          sp2 (Specie): Second specie.
          bond_order: For species with different possible bond orders,
              this allows one to obtain the bond length for a particular bond
              order. For example, to get the C=C bond length instead of the
              C-C bond length, this should be set to 2. Defaults to 1.
  
      Returns:
          Bond length in Angstrom. If no data is available, the sum of the atomic
          radius is used.