code: def _breakend_orientation(strand1, strand2):
      
      EndOrientation = namedtuple("EndOrientation",
                                  ["is_first1", "is_rc1", "is_first2", "is_rc2"])
      if strand1 == "+" and strand2 == "-":
          return EndOrientation(True, True, False, True)
      elif strand1 == "+" and strand2 == "+":
          return EndOrientation(True, False, True, False)
      elif strand1 == "-" and strand2 == "-":
          return EndOrientation(False, False, False, False)
      elif strand1 == "-" and strand2 == "+":
          return EndOrientation(False, True, True, True)
      else:
          raise ValueError("Unexpected strand pairing: {0} {1}".format(
              strand1, strand2))
docs: Convert BEDPE strand representation of breakpoints into VCF.
  
      | strand1  |  strand2 |     VCF      |
      +----------+----------+--------------+
      |   +      |     -    | t[p[ ]p]t    |
      |   +      |     +    | t]p] t]p]    |
      |   -      |     -    | [p[t [p[t    |
      |   -      |     +    | ]p]t t[p[    |