A ParserError is raised when trying to parse a report with multiple BECOMING (BECMG) groups:

Unparsed groups in body 'BECMG FM1000 TL1020 6000 NSW' while processing 'METAR WSSS 280900Z 26009KT 180V350 0600 R20R/1900D R20C/1600D +TSRA FEW008 SCT013CB FEW015TCU 24/23 Q1010 BECMG FM0920 TL0930 3000 TSRA BECMG FM1000 TL1020 6000 NSW'

Unparsed groups in body 'BECMG FM1920 TL1940 6000 NSW' while processing 'METAR WSSS 311900Z 28009KT 210V320 1800 +TSRA FEW010 FEW014CB BKN015TCU 25/24 Q1011 BECMG TL1920 4000 TSRA BECMG FM1920 TL1940 6000 NSW'

Unparsed groups in body 'BECMG FM1955 TL2010 6000 NSW' while processing 'METAR WSSS 311930Z VRB05KT 1800 +TSRA FEW008 FEW014CB SCT015TCU 25/24 Q1011 BECMG FM1940 TL1955 4000 TSRA BECMG FM1955 TL2010 6000 NSW'

Unparsed groups in body 'BECMG FM2020 TL2040 6000 NSW' while processing 'METAR WSSS 312000Z VRB04KT 2000 +TSRA FEW010 FEW014CB SCT040 BKN140 24/24 Q1011 BECMG TL2020 4000 -TSRA BECMG FM2020 TL2040 6000 NSW'