code: def trim_shared_flanking_strings(ref, alt):
      
      ref, alt, prefix = trim_shared_prefix(ref, alt)
      ref, alt, suffix = trim_shared_suffix(ref, alt)
      return ref, alt, prefix, suffix
docs: Given two nucleotide or amino acid strings, identify
      if they have a common prefix, a common suffix, and return
      their unique components along with the prefix and suffix.
  
      For example, if the input ref = "SYFFQGR" and alt = "SYMLLFIFQGR"
      then the result will be:
          ("F", "MLLFI", "SY", "FQGR")