#def mm_to_um(mm): return mm * 1000

def mm_to_nm(mm): return mm * 1000000

def mm_to_micron(mm): return mm

def um_to_mm(um): return um / 1000

def um_to_nm(um): return um * 1000

def um_to_micron(um): return um / 1000

def nm_to_mm(nm): return nm / 1000000

def nm_to_um(nm): return nm / 1000

def nm_to_micron(nm): return nm / 1000000

def micron_to_mm(micron): return micron

def micron_to_um(micron): return micron * 1000

def micron_to_nm(micron): return micron * 1000000

def convert_length(): value = float(input("Enter the measurement value: ")) from_unit = input("Enter the current unit (mm, um, nm, micron): ") to_unit = input("Enter the target unit (mm, um, nm, micron): ")

result = 0

if from_unit == "mm": if to_unit == "um": result = mm_to_um(value) elif to_unit == "nm": result = mm_to_nm(value) elif to_unit == "micron": result = mm_to_micron(value) else: print("Invalid target unit.") return elif from_unit == "um": if to_unit == "mm": result = um_to_mm(value) elif to_unit == "nm": result = um_to_nm(value) elif to_unit == "micron": result = um_to_micron(value) else: print("Invalid target unit.") return elif from_unit == "nm": if to_unit == "mm": result = nm_to_mm(value) elif to_unit == "um": result = nm_to_um(value) elif to_unit == "micron": result = nm_to_micron(value) else: print("Invalid target unit.") return elif from_unit == "micron": if to_unit == "mm": result = micron_to_mm(value) elif to_unit == "um": result = micron_to_um(value) elif to_unit == "nm": result = micron_to_nm(value) else: print("Invalid target unit.") return else: print("Invalid current unit.") return

print(f"{value} {from_unit} is equal to {result} {to_unit}.")

Main function for testing

def main(): convert_length()

if name == "main": main()