code: def normalize_species_name(name):
      
      lower_name = name.lower().strip()
  
      # if given a common name such as "human", look up its latin equivalent
      if lower_name in Species._common_names_to_species:
          return Species._common_names_to_species[lower_name].latin_name
  
      return lower_name.replace(" ", "_")
docs: If species name was "Homo sapiens" then replace spaces with underscores
      and return "homo_sapiens". Also replace common names like "human" with
      "homo_sapiens".