Convert filament length to filament weight and vice versa

fil.py

PLA = 1.24
ABS = 1.03

def _normalize_density(d):
  """Density can be specified as g/cm^3 (common way) or kg/m^3 (SI way).                           
                                                                                                   
  Assumes we are not dealing with degenerate matter!                                               
  """
  return (d < 25) and (d * 1000) or d


def l2w(length, diameter=2.85, density=PLA):
  """length in meters to weight in kilograms."""
  return length * (.785e-6 * diameter * diameter * _normalize_density(density))

def w2l(weight, diameter=2.85, density=PLA):
  """weight in kilograms to length in meters."""
  return weight / (.785e-6 * diameter * diameter * _normalize_density(density))