docs: def constant(constanttype):
      """
      Get A Constant
      """
      constanttype = constanttype.lower()
      if constanttype == 'pi':
          return math.pi
      elif constanttype == 'e':
          return math.e
      elif constanttype == 'tau':
          return math.tau
      elif constanttype == 'inf':
          return math.inf
      elif constanttype == 'nan':
          return math.nan
      elif constanttype in ['phi', 'golden']:
          return (1 + 5**0.5) / 2