C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o: In function `SevenSegmentExtended::printTime(unsigned char, unsigned char, bool) [clone .constprop.25]':

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:20: undefined reference to `SevenSegmentTM1637::getColonOn()'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:21: undefined reference to `SevenSegmentTM1637::setColonOn(bool)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:25: undefined reference to `SevenSegmentTM1637::encode(int)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:26: undefined reference to `SevenSegmentTM1637::encode(int)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:27: undefined reference to `SevenSegmentTM1637::encode(int)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:28: undefined reference to `SevenSegmentTM1637::encode(int)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:30: undefined reference to `SevenSegmentTM1637::printRaw(unsigned char const*, unsigned int, unsigned char)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:35: undefined reference to `SevenSegmentTM1637::setColonOn(bool)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:36: undefined reference to `SevenSegmentTM1637::printRaw(unsigned char, unsigned char)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:38: undefined reference to `SevenSegmentTM1637::setColonOn(bool)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:39: undefined reference to `SevenSegmentTM1637::printRaw(unsigned char, unsigned char)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:42: undefined reference to `SevenSegmentTM1637::setColonOn(bool)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o: In function `__base_ctor ':

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:5: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o: In function `__static_initialization_and_destruction_0':

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:21: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o: In function `__base_ctor ':

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:5: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:5: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o: In function `__static_initialization_and_destruction_0':

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:29: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o: In function `__base_ctor ':

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:5: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:5: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o: In function `__static_initialization_and_destruction_0':

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:39: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o: In function `__base_ctor ':

C:\Users\skipp\Desktop\arduino-1.8.5\libraries\TM1637-master/SevenSegmentExtended.cpp:5: undefined reference to `SevenSegmentTM1637::SevenSegmentTM1637(unsigned char, unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o:(.rodata+0x28): undefined reference to `SevenSegmentTM1637::write(unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans1.ltrans.o:(.rodata+0x2a): undefined reference to `SevenSegmentTM1637::write(unsigned char const*, unsigned int)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans0.ltrans.o: In function `setup':

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:71: undefined reference to `SevenSegmentTM1637::begin(unsigned char, unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:72: undefined reference to `SevenSegmentTM1637::begin(unsigned char, unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:73: undefined reference to `SevenSegmentTM1637::begin(unsigned char, unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:74: undefined reference to `SevenSegmentTM1637::begin(unsigned char, unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:75: undefined reference to `SevenSegmentTM1637::begin(unsigned char, unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans0.ltrans.o:C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:76: more undefined references to `SevenSegmentTM1637::begin(unsigned char, unsigned char)' follow

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans0.ltrans.o: In function `setup':

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:80: undefined reference to `SevenSegmentTM1637::setBacklight(unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:81: undefined reference to `SevenSegmentTM1637::setBacklight(unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:82: undefined reference to `SevenSegmentTM1637::setColonOn(bool)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:83: undefined reference to `SevenSegmentTM1637::setBacklight(unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:84: undefined reference to `SevenSegmentTM1637::setBacklight(unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:85: undefined reference to `SevenSegmentTM1637::setBacklight(unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:86: undefined reference to `SevenSegmentTM1637::setBacklight(unsigned char)'

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:87: undefined reference to `SevenSegmentTM1637::setBacklight(unsigned char)'

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans0.ltrans.o:C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:88: more undefined references to `SevenSegmentTM1637::setBacklight(unsigned char)' follow

C:\Users\skipp\AppData\Local\Temp\ccC8ynUU.ltrans0.ltrans.o: In function `setup':

C:\Users\skipp\Downloads\CODE_delorean_clock/CODE_delorean_clock.ino:90: undefined reference to `SevenSegmentTM1637::setColonOn(bool)'

collect2.exe: error: ld returned 1 exit status